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Following up on my previous question on the enduring properties of a book on algorithms, see here, now I would like to ask the community what language would you use to write the examples of such a reference book.
I will probably not use MMIX (!) to write the examples of the book, but at the same time, I think just pseudo-code would be less interesting than examples in a real language.
Still, I'd also like the book to be a resource for researchers as well. What could be the choice of the community? Why?
Answer: I knew this was a tough question and that there would be several different answers. Notice that answers cover the whole range from Assembly/MMIX(!!) to Python and pseudo-code. The votes and the arguments compel me to choose Uri's sensible answer, with one caveat: my pseudo-code will be as close to C as I possibly can (without going into platform specific issues, of course), and I will possibly discuss better implementations in side notes (As all of us know, mathematically proving the algorithm works is far, far from the problems of implementing it).
The book is on algorithms in a particular domain, not on the mathematics of algorithms in general (much smarter people have done and will do much better than me on general algorithms). As such, one thing I consider would add value to such a book is the repository of the algorithms, which I will definitely put online in a companion website (maybe in a couple of languages, if I find the time).
Thanks for all the answers. I sometimes feel I should put everybody who answers as co-authors. :)
A good book on algorithms should be written in psueod-code a-la-CLR...
In my experience, most books that go into language-specific examplse end up looking more like undergraduate textbook than like a serious reference or learning books. In addition, most languages are fairly clunky when dealing with collections (esp. C++ and Java, even with generics). Between all the details, too much is lost. You're also immediately eliminating a lot of your potential audience.
The only advantage to language specific books is that if you were writing a textbook, the publisher could attach a CD and add 50$ to the MSRP.
It's easier for me to understand an algorithm from (readable) pseudocode. If I can't figure out how to implement it in my language with my own collections, I'm in trouble anyway.
You could add to every pseudocode listing a note about implementation details for specific languages (e.g., use a TreeSet in Java for best performance, etc.)
You could also maintain a separate website for the book (good idea anyway) where you'll have actual implementations in different languages. No need to kill trees with long printouts.
Use a real programming language -- never a psuedo one. Readers are very suspicious
of psuedo code , readers like real programming languages. The trap with psuedo languages is that you can define code concepts that the reader cannot impliment in their language of choice
A real programming language has a number of advantages :
1) you can test your code, hopefuly proving your code correct !
2) you can export that code into a published format for insertion in your book,
ensuring that anybody following your code would be looking
at actual executable code.
3) you would not have to defend you psuedo code.
The choice of language is obvously subjective, but I think that almost any modern language
could be used, but I'd recommend one that has 'least overheads' in terms of quick understanding. And perferably one that the reader can get a compiler/interpreter.
If you'd like to use C, then perhaps you should check out D. An improved C.
For example, Ruby is of this ilk if you keep you code 'simple',
Java is not ( too many support libraries required),
in an earlier time Pascal would be a candidate.
BTW: I dont use Ruby now, as I currently use Smalltalk & REBOL, but I would not use
either of those languages in a book. Your book would go straight to the remainder bin !
I would avoid anything that abstracts the core 'mechanics' of any particular algorithm
There is a tremendous benefit in Knuth's rendering of the algorithms in an assembly level language. It forces the reader to carefully consider exactly what is going on in the silicon when we code algorithms in some higher level language. Especially for systems programmers, this kind of understanding can't be gotten any other way.
Knuth's new MMIX is ideal: consider it an assembly level pseudo-code.
My ideal textbook would have algorithms written in pseudocode and MMIX, so that we can see the algorithm in both its pretty and gory-complex forms. Pseudo-code should be preferred to "real languages", because it sidesteps pointless "you should have used this language not that language" battles. At this stage, pseudocode needs no defending -- the best extant algorithms textbooks use either pseudocode or in Knuth's case a kind of assembly pseudocode.
The choice is not going to be able to please everyone.
Robert Sedgewick has written his "Algorithms in..." books in multiple languages. I had the C version for a course and bought the C++ version when I started working with C++ at work.
You can't escape language features (even pseudo language features).
To try to please as many people as possible you could choose two languages, say one functional and one not. It could help illustrate motivations in algorithm choice.
C style is often used because many languages use a very similar style so most programmers understand it without explanation. Further, examples can be run on any machine with a C compiler - which is nearly every machine.
However, higher level concepts often require the use of more recent technologies and techniques - OO, functional programming, etc.
These are often expressed in the language that has the required features. Java, C#, Erlang, Ada, etc - most good programmers will grasp what is going on with just a little explanation.
But C is very nearly a universal foundation - you really can't go wrong if you adopt a C style for examples.
-Adam
I would not use any specific language. Use a pseudo-language that will be clear to most anyone who has done a little programming. Usually these books use something close to the C style, but that is not a rule. I know that you mention that you do not want to use pseudo code, but that will allow you to reach a broader audience.
I would use something that lets you express exactly the idea behind the algorithm.
Haskell is quite neat, but I think that with algorithms that work with state, it can get in your way, and you would be more occupied with the language than with the algorithm.
I wouldn't use C or its descendants (C++, C#, Java ...) because they will get in your way when your algorithms are more "functional" in nature. Again, you would be more occupied with the language than with the algorithm. I would feel very uncomfortable if I had to work without higher order functions.
So, basically, I would use a multi-paradigm language that you are comfortable with, and with which you feel confident that you can express the algorithms without diving into language specifics.
My personal choice would be something like Common Lisp, but perhaps Python or Scala is workable, too.
Python's a good choice all around. It's very readable, even if you haven't programmed in it before. Plus, it's a lot less verbose than some other common language choices.
Related
Brief Description
I have a college work where I have to implement a graph library (I'll have to give a presentation about this work later)
The basic idea is to write all the code of the data structures and their algorithms from scratch, using the tools provided by some programming language, like C/C++, Java, Python, doesn't really matter which one of them I'll pick at first.
But I should not use any built-in graph libraries in the language: the goal of the work is to make the students learn how these algorithms work. There are some test cases which my program will be later submitted to.
It is not really necessary but, if you wanna take a look, here is the homework assignment: http://pastebin.com/GdtvMTMR (I used Control-C Control-V plus google translate from a LaTeX text, this is why the formatting is poor).
The Question
So, my question is: which programming language would be more time efficient to implement this library?
It doesn't really matter if the language is functional, structured or object oriented. My priority is time efficiency and performance.
The better language is the one you know more.
But if you're looking for some performance, take a look at compiled languages with optimisations. Keep in mind that the code you write is the major component responsible in final performance, the language itself cant do miracles.
A more low level language give to you controls but requires deeply knowledge of the language and the machine you're running your code, so it's a tradeoff.
By a personal choose I would recommend C/C++ to implement a graph library. I've already done this in the past and I used vanilla ANSI C and the performance was awesome.
The one you feel more passionate about and feel more comfortable coding with.
This way you will rock your project.
Myself would pick Java.
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As I am in my starting career year in software development (C++ & C#) I now see my flaws and what I miss in this sphere. Because of that I came into some conclusions and made myself a plan to fill those gaps and increase my knowledge in software development. But the question I stumbled upon after making a tasks which I need to do has not quite obvious answer to me. What is the priority of those tasks? Here are these tasks and my priority by numbering:
Learning:
Functional programming (Scala)
Data structures & Algorithms (Cormen book to the rescue + TopCoder/ProjectEuler/etc)
Design patterns (GOF or Head First)
Do you agree with this tasks and priorities? Or do I miss something here? Any suggestions are welcome!
I think you have it backwards. Start with design patterns, which will help you reduce the amount messy code you produce, and understand better code made by other people (particularly libraries written with design patterns in mind).
In addition to the book of four, there are many other design pattern books -- Patterns of Enterprise Application Architecture, for example. It might be worth looking at them after you get a good grounding. But I also highly recommend Domain Driven Design, which I think gives you a way of thinking about how to structure your program, instead of just identifying pieces here and there.
Next you can go with algorithms. I prefer Skiena's The Algorithm Design Manual, whose emphasis is more on getting people to know how to select and use algorithms, as well as building them from well known "parts" than on getting people to know to make proofs about algorithms. It is also available for Kindle, which was useful to me.
Also, get a good data structures book -- people often neglect that. I like the Handbook of Data Structures and Applications, though I'm also looking into Advanced Data Structures.
However, I cannot recommend either TopCoder or Euler for this task. TopCoder is, imho, mostly about writing code fast. Nothing bad about it, but it's hardly likely to make a difference on day-to-day stuff. If you like it, by all means do it. Also, it's excellent preparation for job interviews with the more technically minded companies.
Project Euler, on the other hand, is much more targeted at scientific computing, computer science and functional programming. It will be an excellent training ground when learning functional programming.
There's something that has a bit of design patterns, algorithms and functional programming, which is Elements of Programming. It uses C++ for its examples, which is a plus for you.
As for functional programming, I think it is less urgent than the other two. However, I indicate either Clojure or Haskell instead of Scala.
Learning functional programming in Scala is like learning Spanish in a latino neighborhood, while learning functional programming in Clojure is like learning Spanish in Madrid, and learning functional programming in Haskell is like learning Spanish in an isolated monastery in Spain. :-)
Mind you, I prefer Scala as a programming language, but I already knew FP when I came to it.
When you do get to functional programming, get Chris Okasaki's Purely Functional Data Structures, for a good grounding on algorithms and data structures for functional programming.
Beyond that, try to learn a new language every year. Even if not for the language itself, you are more likely to keep up to date with what people are doing nowadays.
Data structures and algorithms will help you no matter what language you use. I'd work on it first. Then design patterns (any OOP language will benefit from them). Functional programming is nice, but not necessarily a top priority.
Depends entirely on what you're doing.
I'd tailor which one you learn first to what would help you the most with your current job.
Write lots of code. Try to do it better every time. Occasionally work with more senior people, who can provide guidance praise and gentle correction.
I think that in general the topics that you have picked are very important, and my give you the chance to do something more than the usual boring stuff. However, I believe that the order should be something like this:
Data structures & Algorithms
Functional programming
Software Design
Specific technologies you need
My opinion is that Algorithms and data structures should be first. It is very hard to study algorithms if you have a lot of other things in you head (good coding practices, lots of programming paradigms, etc.). Also with time, people tend to become more lazy, and lose the patience to get into the ideas of this complex matter. On the other hand, missing some fundamental understanding about how things can be represented or operate, may lead to serious flaws in understanding anything more sophisticated. So, assuming that you have some ideas about imperative programming (the usual stuff tаught in the introductory courses) you should enhance your knowledge with algorithms and data structures.
It is important to have at least basic understanding of other paradigms. Functional programming is a good example. You may also consider getting familiar with logic programming. Having basic understanding of Algorithms and Data Structures will help you a lot in understanding how such languages work. I don't know whether Scala is the best language for that purpose, but will probably do. Alternatively, you can pick something more classic like Lisp, or Scheme. Haskell is also an interesting language.
About the Design Patterns... knowing design patterns will help you in doing object oriented design, but you should be aware, that design patterns are just a set of solutions to popular problems. Knowing Design Patterns is by no means that same as knowing how to design software. In order to improve you software design skills you should study other materials too. A good example from where you can get understanding about these concepts is the book Code Complete, or the MIT course 6.170 (its materials are publicly available).
At some point you will need to get into the details of a specific framework (or frameworks) that you will need for what you do. Keep in mind, that such frameworks change, and you should be able to adapt, and learn new technologies. For instance, knowing ASP.NET MVC now, may be worthless 5 years from now (or may not be, who knows?).
Finally, keep in mind, that no matter what you read, you need to practice a lot, which means solving problems, writing code, designing software, etc. Most of these concepts can not be easily explained, or even expressed with words, so you will need to reach most of them by yourself, (that is, you will need to reinvent the wheel many times).
Good luck with your career!
If would think Functional Programming would be low in priority since the languages you use are OO in nature, I would think spending some time in Design Patterns and on the specifics of the language itself would be more useful.
I read both GOF and HeadFirst, HeadFirst is probably the easier and more fun of the 2 but much thicker. You should probably look at Enterprise Design Patterns, like Martin Fowler's page http://martinfowler.com/eaaCatalog/
What field do you think you will work in? Games ? Web? That will probably decide how important the Algo part would be for.
I would say that you first need to understand (even if not remember) the base algorithms and data structures. (use Knuth and Cormen), then get to learn architecture (design patterns are here.)..
Functional programming is just one type of programming and is mandatory. There are many great programmers that are not using functional programming, but I assume that for all kinds you must first know the basics- algorithms and data structures.
I'd say #2 goes first, especially if you are planning to use C++/C# at work, having a good command of data structures and algorithms will give you some edge. I see #1 and #3 as somewhat parallel paths, but I do have a couple of suggestions: start with the Head First book for patterns, the GOF is more like a reference book and also the notation and language may get quite abstruse. As for functional programming, may I suggest Clojure instead of Scala? I'm convinced that a "functional-first" language (like F# or Clojure) will force you to think functional (a good thing) instead of just patching your O-O/imperative skills.
I'm really interested in becoming a serious programmer, the type that people admire for hacker chops, as opposed to a corporate drone who can't even complete FizzBuzz.
Currently I've dabbled in a few languages, most of my experience is in Perl and Shell, and I've dabbled slightly in Ruby.
However, I can't help but feel that although I know bits and pieces of languages, I don't know how to program.
I'm really in no huge rush to immediately learn a language that can land me a job (though I'd like to do it soon), and I'm considering using PLT Scheme (now called Racket) to work through How to Design Programs or Structure and Interpretation of Computer Programs, essentially, one of the Scheme classics, because I have always heard that they teach people how to write high-quality, usable, readable code.
However, even MIT changed its introductory course from using SICP and Scheme to one in Python.
So, I ask for the sage advice of the many experienced programmers here regarding the following:
Does Scheme (and do those books) really teach one how to program well? If so, which of the two books do you recommend?
Is this approach to learning still relevant and applicable? Am I on the right track?
Am I better off spending my time learning a more practical/common language like Python?
Is Scheme (or lisp in general) really a language that one learns, only to never use? Or do those of you who know a lisp code in it often?
Thanks, and sorry for the rambling.
If you want to learn to really program, start doing it. Quit dabbling and write code. Pick a language and write code. Solve problems and release applications. Work with experienced programmers on open source projects, but get doing. A lot.
Does Scheme (and do those books) really teach one how to program well? If so, which of the two books do you recommend?
Probably. Probably better than any of the Learn X in Y Timespan books.
Is this approach to learning still relevant and applicable? Am I on the right track?
Yes.
Am I better off spending my time learning a more practical/common language like Python?
Only if you plan to get a job in it. Scheme will give you a better foundation though.
Is Scheme (or lisp in general) really a language that one learns, only to never use? Or do those of you who know a lisp code in it often?
I do emacs elisp fiddling to adjust my emacs. I also work with functional languages on the side to try to keep my mind flexible.
My personal opinion is that there are essentially two tracks that need to be walked before the student can claim to know something about programming. Track one is the machine itself, the computer. You should start with assembly here and learn how the computer works. After some work and understanding there - don't skimp - you should learn C and then C++; really getting the understanding of resource management and what really happens. Track two is the very high level language track - Scheme, Prolog, Haskell, Perl, Python, C#, Java, and others that execute on a VM or interpreter lie in this area. These, too, need to be studied to learn how problems can be abstracted and thought about in different ways that do not involve the fiddly bits of a real computer.
However, what will not work is being a language dilettante when learning to program. You will need to find a language - Scheme is acceptable, although I'd recommend starting at the low level first - and then stick with that language for a good year at least.
The most important parts of Scheme are the programming-language concepts you can pick up that modern languages are now just adopting or adding support for.
Lisp and Scheme have supported, before most other languages, features that were often revolutionary for the time: closures and first-order functions, continuations, hygienic macros, and others. C has none of these.
But they're appearing more and more often in programming languages that Get Stuff Done today. Why can you just declare functions seemingly anywhere in JavaScript? What happens to outside variables you reference from within a function? What are these new "closures" that PHP 5.3 is just now getting? What are "side effects" and why can they be bad for parallel computing? What are "continuations" in Ruby? How do LINQ functions work? What's a "lambda" in Python? What's the big deal with F#?
These are all questions that learning Scheme will answer but C won't.
I'd say it depends on what you want to do.
If you want to get into programming, Python is probably better. It's an excellent first language, resembles most common programming languages, and is widely available. You'll find more libraries handy, and will be able to make things more easily.
If you want to get into computer science, I'd recommend Scheme along with SICP.
In either case, I'd recommend learning several very different languages eventually, to give you more ways to look at and solve problems. Getting reasonably proficient in Common Lisp, for example, will make you a better Java programmer. I'd take them one at a time, though.
The best languages to start with are probably:
a language you want to play/learn in
a language you want to work in
And probably in that order, too, unless the most urgent need is to feed yourself.
Here's the thing: the way to learn to program is to do it a lot. In order to do it a lot, you're going to need a lot of patience and more than a little bit of enthusiasm. This is more important than the specific language you pick.... but picking a language that you like working in (whether because you like the features or because you feel it'll teach you something) can be a big boost.
That said, here's a couple of comments on Scheme:
Does Scheme (and do those books)
really teach one how to program well?
The thing about Scheme (or something like it) is that if you learn it, it'll teach you some very useful abstractions that a lot of programmers who don't ever really come to grips with a functional programming language never learn. You'll think differently The substance of programming languages and computing will look more fluid to you. You'll have a better idea of how to compose your own quasi-primitives out of a very small set of primitives rather than relying on the generally static set of primitives offered in some other languages.
The problem is that a lot of what I'm saying might not mean much to you at the moment, and it's a bit more of a mind-bending road than coming into a common dynamic language like Perl, Python, or Ruby... or even a language like C which is close to the Von Neumann mechanics of the machine.
This doesn't mean it's necessarily a bad idea to start there: I've been part of an experiment where we taught Prolog of all things to first-time programmers, and it worked surprisingly well. Sometimes beginner's mind actually helps. :) But Scheme as a first language is definitely an unconventional path. I suspect Ruby or Python would be a gentler road.
Is Scheme (or lisp in general) really
a language that one learns, only to
never use?
It's a language that you're unlikely to be hired to program in. However, while you're learning to program, and after you've learned and are doing it in your free time, you can write code in whatever you want, and because of the Internet, you'll probably be able to find people working on open source projects in whatever language you want. :)
I hate to tell ya, but nobody admires programmers for their "hacker chops". There's people who get shit done, then there's everyone else. A great many of the former types are the "corporate drones" you appear to hold in contempt.
Now, for your question, I personally love Lisp (and Scheme), but if you want something you're more likely to use in industry "Beginning Python" might be better material for you as Python is found more often in the wild. Or if you enjoy Ruby, find some good Ruby material and start producing working solutions (same with Java or .Net or whatever).
Really, either route will serve you well. The trick is to stick with it until you've internalized the concepts being taught.
Asking whether an approach to learning is relevant and applicable is tricky - there are many different learning styles, and it's a matter of finding out which ones apply to you personally. Bear in mind that the style you like best might not be the one that actually works best for you :-)
You've got plenty of time and it sounds like you have enthusiasm to spare, so it's not a matter of which language you should learn, but which one you should learn first. personally, I'd look at what you've learnt so far, what types of languages and paradigms you've got under your belt, and then go off on a wild tangent and chose one completely different.
I started programming at a very very young age. When I was in high school, I thought I was a good programmer. That's when I started learning about HOW and WHY the languages work rather than just the syntax.
Before learning the how and why, switching to a new language would have been hell. I had learned a language, but I hadn't learned to program. Now that I know the fundamental concepts well, I can apply them to virtually any language and pick it up with ease.
I would highly recommend a book (or even a school coarse, if you can afford it) that takes you through the processes of coding without relying on a specific language.
Unfortunately I don't have any books to recommend, but if others agree with me and know of any, maybe they can offer a suggestion.
//Edit: After re-reading your question, I realize that I may have not actually answered any of them... Sorry about that. I think picking up a book that will take you in-depth with best-practices would be extremely helpful, regardless of the language you choose.
There are basic programming concepts (logic flow, data structures), which are easily taught by using languages like Python. However, there are much more complex programming concepts (design patterns, optimization, threading, etc.) which the classic languages don't abstract away for you.
If your search for knowledge leans more toward algorithm development and the science of programming, start with C. If your search is more for a practical ends, I hear Ruby is a good starting point.
I agree with gruszczy. I'd start programming with C.
It may be kind of scary at first (at least for me :S ) but in the long run you'd be grateful it. I mean I love Python, but because I learned C first, the learning curve for other languages wasn't very steep at all.
Start with C and make it so.
Just remember to practice, because you'll never improve at something by doing nothing. ;)
To a specific point in your question, the "classics" you mention will help you with exactly what the titles say. SICP is about the structure and interpretation of computer programs. It is not about learning Scheme (though you will learn Scheme). HtDP is about how to design programs, it is not about learning Scheme (though you will learn Scheme).
Scheme, in principle, is a very small and concise language with almost no gotchas. This makes it excellent for moving on to learning how to structure and interpret programs, or how to design them. More traditional "practical" languages like C, C++, Python, or Java do not have this quality. They are rife with syntax. Learning with these languages means you must simultaneously learn syntactical quirks while learning to think like a programmer. In my opinion, this is unfortunate. In some cases the quirks are good, in others they are accidents of history, but in all cases it is unfortunate.
Start coding in C. It should be a horror for you at first, but this teaches you most important stuff like: pointers, recurrence, memory management. Try reading some classic books about programming like The Art of Computer Programming by Donald Knuth. After you master that, you can think about learning object oriented programming or functional programming. First basics. If fou manage to learn them, nothing will be hard for you ever again.
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I've got a little experience with Python (enough to where I can do if/else/elif and some random number generation), but I've always had a weird fascination with the Lisp languages. I downloaded some scheme source code to look at the syntax but it was pretty much gibberish to me.
For a programmer with only a little programming experience like myself, given some good books, websites, and some time, would it be particularly difficult to learn either Common Lisp or Scheme?
Which of the two would be easier? How do they compare with Python and C, as far as ease of learning?
Thanks
Get SICP (Structure and Interpretation of Computer Programs). It was the entry level CS class textbook at MIT up until very recently. It is entirely based on Scheme. If you enjoy CS at all, you will love this book. It's fantastic. You'll walk away a much better programmer too after reading it (and ideally doing most of the exercises). It's an ideal beginner's book, it starts at the very beginning and eases you up to being quite competent at Scheme. However, it is a college textbook, so unless you have a bit of a knack for programming, it may be a tad on the tough side.
Given some good books, websites, and some time, would it be particularly difficult to learn either Common Lisp or Scheme?
No.
Which of the two would be easier?
Scheme, because
It has better books for beginners.
It has a superb interactive programming environment designed for people who are just learning the language.
It is smaller.
How do they compare with Python and C, as far as ease of learning?
I think it's harder to learn C than to learn either Python or Scheme, because to learn C you really have to grok the machine model, pointers, and dynamic memory.
Between Scheme and Python, it is really hard to predict how any individual learner will react. I really like Python's significant whitespace, and I find Scheme's parentheses annoying and distracting. Lots of people really like Scheme's parentheses, and they find Python's significant whitespace annoying and distracting. (There are important semantic differences, but it is hard to escape the tyranny of syntax.)
What books should I use? (question you should have asked and didn't)
Don't use Structure and Interpretation of Computer Programs (SICP). That book's point of view is "let's show off how smart we are by coding all of computer science in Scheme." The book is a tremendous intellectual tour de force, but it is not at all suitable for beginners. When MIT used it in 6.001, it was as a "weedout" course because 30–40% of all MIT students wanted to major in EECS, and they were trying to turn people away. SCIP is a terrific for a senior CS student or a programmer with 5 years of experience. Don't try to learn from it.
Some good books to learn from:
How to Design Programs by Felleisen et al has been carefully crafted and honed through years of experience. It uses Scheme and teaches you exactly what it claims in the title. Highly recommended.
Simply Scheme by Harvey and Wright is an introductory CS book by people who felt that SCIP needed a "prequel." I enjoyed reading it but I haven't taught from it.
If you can stand cuteness, The Little Schemer by Felleisen and Friedman has a very unusual dialectical style, with tons of examples, that you might like.
Get
"The Little Schemer"
and
"The Advanced Schemer"
These books are INVALUABLE as programming concept aides. I'd personally do them before SICP just because SICP is a bit fast if you haven't programmed much before... and even if you have they're great books!
I personally think of Scheme as a very good pedagogical language. It can be used for just about anything I suppose, but it's very good for teaching programming constructs without getting bogged down in syntactical issues. The closest thing to pure semantics you're going to get.
I would recommend going with Common Lisp.
It has excellent implementations that provide a variety of different capabilities. The best ones are still the commercial implementations (though they have no-cost versions for learning Lisp) like Allegro CL from Franz and LispWorks. They offer extensive libraries and include GUI-based development environments. But the open source and free implementations are excellent, too: SBCL, CCL, ECL, CLISP, ...
There are a bunch of excellent books for Lisp, like Peter Seibel's Practical Common Lisp.
Learning Common Lisp is not that difficult, but getting deeper experience get take some time, because the language and its eco-system is surprisingly rich.
Learning Scheme is useful, too. Also learning SICP can help. But there is no immediate need, since the Lisp literature talks about many of the same issues. Unfortunately Scheme lost some of its appeal in recent years (I find the latest R6RS to be totally disappointing) and I find also implementations like 'Racket' to be moving in the wrong direction. Instead one might want to learn some of the better ML dialects and implementations (say, OCAML). Though it might be interesting to check out various Scheme implementations, there are some with interesting capabilities.
The core ideas you should learn from Lisp are these:
multi-paradigm programming
programmable programming language
symbolic computation
interactive and exploratory development
Learn how Lisp supports these ideas and why they are important.
Lisp isn't hard to learn. It can be taught poorly, and it does have some "high level" concepts, especially if you're coming from the imperative "classic" programming world.
But today, may of the modern languages have aspects very similar to what Lisp offers, so there is likely not much "new" in Lisp compared to other languages, especially Python.
My "hurdle" with Lisp (and Scheme) was simply "lambda". Essentially, my fundamental problem was I had nothing to relate to what a "lambda" was, why it was called "lambda", etc.
If it was named "function" or "routine" or something, it would have been trivial. But as is, the word "lambda" was meaningless in every way. They could have called it "mork", "bleem", or "fizbin" and it would have been as useful.
Once I grokked "lambda", the rest fell in to place.
If you're interested a A Lisp (i.e. a language which is essentially from the Lisp family), then Scheme is a good choice. But, Scheme is NOT Common Lisp (which is what "Lisp" typically means today), they are really different languages.
If you want to learn Common Lisp, I would start with Common Lisp and skip Scheme.
You can look to Practical Common Lisp to get you in to writing Lisp without "having to learn it" so to speak.
You can actually find a full video course of Structure and Interpretation of Computer Programs on Google Video. Start here: http://video.google.com/videoplay?docid=933300011953693438#
The videos were made in the 80's by Hewlett-Packard, and taught by Sussman and Abelson (the original authors). The class is full of HP HW/mechanical engineers who are being retrained as SW engineers. HP released them to the public domain.
Anyone could watch these videos and be a Lisp programmer by the end. Amazing, excellent instructors.
Scheme is (intentionally) more compact than Common Lisp, and you'll find that you can learn the language very quickly. Now, mastering the (any) language and computer science concepts is another story, and #Matt Greer's book suggestion would be a wonderful place to start.
I'd say a Lisp will be easier to learn as a new programmer than if you wait. That's because the way most languages encourage you to think about programming is a handicap to learning Lisp; being experienced with a more conventional language will probably help in some ways, but not with the qualities that make Lisp unique.
Scheme --- the Lisp with which I'm most familiar --- is probably about as easy as Python to learn, especially if you choose PLT Scheme (now renamed Racket), which offers you a lot of helpful extensions. Common Lisp is probably about the same difficulty, though I find it less instinctive for reasons which are probably not universal. I have found C much more difficult than either, for the reasons Norman Ramsey suggests.
What one I'd suggest learning depends very much on what you want to do with it. If you want to learn a crystal-clear language with no frills, whose core can be learned quickly, learn a Scheme that implements the R5RS standard, such as Scheme48. If you want a more capable Scheme, either immediately or later on, learn PLT Scheme/Racket. If you want a big, friendly, diffuse language of immense power but not as visibly internally consistent as Scheme, choose Common Lisp; Steel Bank Common Lisp is a good implementation.
As to which is easier, Lisp or Scheme, being "dialects" of the Lisp family, at the beginner level they are pretty much the same thing and interchangeable. I learned Common Lisp from Peter Siebel's "Practical Common Lisp", then picked up SICP and worked through all the exercises through the first two chapters using Common Lisp rather than Scheme. There are just a few different keywords and things like the use of funcall in CL where just a pair of parentheses would suffice in Scheme.
Both Siebel's book and SICP are available for free in their entirety on the web. Download them and get hackin'!
Last time I checked the lectures from the intro classes for CS61A at Berkeley which used SICP were available from iTunes, which would give you a full lecture series to help you learning the language. For free! I TA'd for Brian Harvey back in the late 90's and students really liked his lectures.
You can currently find them here: https://archive.org/details/ucberkeley-webcast-PL6879A8466C44A5D5
Consider (the poorly titled) "Programming Languages, An Interpreter-Based Approach" by Samuel N. Kamin. You'll learn how to program in 7 different languages (including Lisp, Scheme, SASL, CLU), plus how to implement interpreters for each. You should come away with a good understanding of how the languages differ, why they're designed the way they are, what are the tradeoffs in using them, etc.
If you are fascinated by the language, i think you will find it easy. But i must say it's not for everyone. I tried several times learning Scheme and Common Lisp and lost interest. When i see an "if" in a programming language, i start looking for "then", "else", an open-brace, a colon, etc. but Lisp has none of that. I only see a soup of parenthesis.
Besides, some concepts are easier in other languages. I agree with the guys who don't like the word "lambda". I really got it when i learned Lua (Javascript is very similar). In Lua and Javascript, when you need an anonymous function, you type (guess what) "function(etc. etc.)". When you want to create a closure by returning a function, you write (guess what) "return function(etc., etc.)". In Lisp, you write "lambda" and use the implicit return at the end of the function. Not very beginner-friendly.
I aslo agree with Norman Ramsey: Don't use Structure and Interpretation of Computer Programs (SICP).
This book is weird. It starts really easy, on page 1 you learn some expressions like (+ 137 349). Easy as pie. Then, on page 2 you learn functions. On page 3 you learn recursion. On page 4 you learn higher-order functions with lambdas (!!!). On page 5 onwards, you say WTF and can't make sense of anything. The book has only 5 chapters each with a thousand pages. It introduces assignment in chapter 3. Maybe your brain is functional, but my brain is certainly imperative and i need to see what the machine is doing: assigning values, copying memory etc. Teaching higher-order functions before assignment is just backwards in my imperative brain. In the last chapter the book talks about compilers, interpreters and garbage-collection. Is this the same book that started teaching expressions like (+ 137 349)? Now i can understand the last chapters of this book, but only after learning half a dozen programming languages of different paradigms and reading a lot about programming languages and their implementation. I don't know how anyone could follow the pace this book imposes on the reader.
Relatively, it's a very difficult language to learn if you are as stubborn as I am :)
Python is an OOP language, and while FP is possible, it's still OOP. Lisp is a FOP language like Haskell. Like Python, it can do OP, but it's still FOP.
Terms used:
OOP = Object Oriented Programming
OP = Object Programming
FOP = Functional Oriented Programming
FP = Functional Programming
I've just started one of my courses, as classes just began 2 weeks ago, and we are learning Scheme right now in one for I assume some reason later on, but so far from what he is teaching is basically how to write in scheme. As I sit here trying to stay awake I'm just trying to grasp why I would want to know this, and why anyone uses it. What does it excel at? Next week I plan to ask him, whats the goal to learn here other than just how to write stuff in scheme.
It's a functional programming language and will do well broaden your experience.
Even if you don't use it in the real world doesn't mean it doesn't have any value. It will help you master things like recursion and help to force you to think of problems in different ways than you normally would.
I wish my school forced us to learn a functional programming language.
Languages like LISP (and the very closely related Scheme) are to programming what Latin is to English.
You may never speak Latin a day in your normal life again after taking a course, but simply learning a language like Latin will improve your ability to use English.
The same is true for Scheme.
I see all these people here saying that while they would never actually use Scheme again it's nevertheless been a worthwhile language to learn because it forces a certain way of thinking. While this can be true, I would hope that you would learn Scheme because you eventually will find it useful and not simply as an exercise in learning.
Though it's not blazingly fast like a compiled language, nor is it particularly useful at serving websites or parsing text, I've found that Scheme (and other lisps by extension) has no parallel when it comes to simplicity, elegance, and powerful functional manipulation of complex data structures. To be honest, I think in Scheme. It's the language I solve problems in. Don't give up on or merely tolerate Scheme - give it a chance and it won't disappoint you.
By the way, the best IDE for Scheme is DrScheme, and it contains language extensions to do anything you can do in another language, and if you find something it can't you can just use the C FFI and write it yourself.
I would suggest to keep an open mind when learning. Most of the time in school we don't fully comprehend what/why we are learning a particular subject. But as I've experienced about a million times in life, it turns out to be very useful and at the very least being aware of it helps you. Scheme, believe it or not, will make you a better programmer.
Some people say Scheme's greatest strength is as a teaching language. While it is very beneficial to learn functional programming (it's an entirely new way of thinking) another benefit in learning scheme is that it is also "pure". Sure it can't do a ton of stuff like java, but that's also what's great about it, it's a language made entirely of parentheses, alphanumeric characters, and a mere handful other punctuations.
In my intro course, we are taught Java, and I see lots of my friends struggling with 'public static void main' even though that's not the point of the program and how the profs have no choice but to 'handwave' it until they're more advanced. You don't see that in Scheme.
If you really want to learn what Scheme can do in a piece of cake that is really hard to implement in languages like Java, I suggest looking at this: http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-12.html#%_sec_1.3
This is probably the best book written on Scheme.
Scheme was used by NASA to program some of the Mars rovers. It's usage in the marketplace is pretty specific, but like I'm sure your teachers are telling you, the things you learn in Scheme will carry over to programming in general.
Try not to get caught up on details like the parenthesis, and car/cdr. Most of what you're learning translates to other languages in one way or another. Don't worry about whether or not you can take Scheme to the market place, chances are you'll be learning some other more marketable languages in other classes. What you are learning here is more important.
If you are learning scheme, you can learn all about how object systems are implemented (hint: an object system isn't always about a type that has methods and instance variables bound to it...). While this kind of knowledge won't help in 95% of your daily work, for 5% of your work you will depend on that knowledge.
Additionally, you can learn about completely different styles of computation, such as streams/lazy evaluation, or even logic programming. You could also learn more about how computer programs in general are interpreted; from the basics in how program code is evaluated, to more deeper aspects like making your own interpreter and compiler). Knowing this kind of information is what separates a good programmer from a great programmer.
Scheme is not really a Functional language, it's more method agnostic then that. Perhaps more to the point, Scheme is an excellent language to choose if you want to explore with different methods of computation. As an example, a highly parallel functional language "Termite" was built on top of Scheme.
In short, the point in learning scheme is so that you can learn the fundamentals of programming.
If you need some help in making programming in scheme more enjoyable, don't be afraid to ask. A lot of programmers get hung up on (for instance) the parenthesis, when there are perfectly great ways to work with scheme source code that makes parenthesis something to cherish, rather then hate. As an example, emacs with paredit-mode,some kind of scheme interaction mode and highlight-parenthesis-mode is pretty awesome.
My problem was when learning this we learned clisp right along with it. I couldn't keep the two strait to save my life.
What I did learn from them though was how to write better c and java code. This is simply because of the different programming style I learned. I have adapted more of the functional style into some of my programming and It has helped me in some cases.
I would never want to program in scheme or lisp again if I didn't have to, but I am glad that I at least did a little in them just to learn the different way to program.
Functional languages like Scheme have great application to mathematics, artificial intelligence, linguistics, and other highly theoretical areas of computer science (machine learning, natural language processing, etc). This is due to the purity of functional programming languages, which have no side effects, as well as their ability to navigate higher-order procedures with ease. A strong knowledge of functional programming languages is critical for solving many of the questions which hover just beyond the frontier of computer science. As a bonus, you'll get great with higher-order procedures and recursion.