In most programming languages, you can mix and match strings with variables during output. However, I can't seem to find a good way to do so. Here is my code:
Prompt A,B
√(A^2+B^2)->C
If iPart(C)≠C
Then
Disp "C = √(",C
Else
Disp "C = ",C
End
Goto ED
Label ED
Unfortunately, with this code, it ends up printing like so:
A? 3
B? 5
C = √(
34
Done
This is not what I want. I would love to be able to have it print C = √(34), but I currently can't find any way to mix variables and strings. Any help would be appreciated.
I know this is a little late, but it might help others as well.
The Output(... command would be used in this case.
Prompt A,B
√(A^2+B^2)->C
If iPart(C)≠C
Then
Disp "C = √(",C
Output(3,7,C
Else
Disp "C = ",C
End
Just remember that the home display is 16x8 characters, which you may need as you plan out how and where to display your results.
Unfortunatelly the "string" command suggested by PGmath doesn't exist on the Ti-83/84/85/86. Actually there is no function for converting a number into a string.
But a possible solution is given here:
http://tibasicdev.wikidot.com/number-to-string2
In ti-basic for the ti-83 the plus (+) is used to concatenate strings. Like this:
Disp "foo"+" "+"bar"
Will output:
"foo bar"
You must remember to convert numbers to strings using string() though:
Disp "C=√("+string(c)+")"
Will output:
"C=√(34)"
Disp "C=√("+c+")" (no string()) will throw an error.
Since version 5.2.0 the ti-83 and 84 (possibly others as well) got the toString( command which can be used to turn a variable into a string. This piece of code will display the variable C with the correct text on the screen.
Disp "Variable C: "+toString(C
Make sure your calculator is using this version though, otherwise you're going to have a hard time finding this command.
I know this thread is very dead but for posterity:
If you have a TI-84+CE on version 5.2 or later, you can use the toString( function.
If you do not, if the output string will always be the same size, simply use Output(. If this does not generate the desired effect, you can use:
:{0,.5,1→L₁
:NL₁→L₂
:Med-Med Y₁
:Equ►String(Y₁,Str1
:sub(Str1,1,length(Str1)-3→Str1
Related
I was doing a code golf (use the minimum number of characters) and I had the following working Python solution. I was trying to shorten my code by re-writing it to Ruby but my Ruby code would always print false.
The code had to read two strings, to ignore the case and to tell whether it was possible to obtain one string by rotating the other string. The output had to be either true or false. Do you have any idea what I did wrong in Ruby?
Python 3 (64 characters) - Works
a=input().lower()
b=input().lower()
print(str(a in 2*b).lower())
Ruby (47 characters) - Always prints "false"
a=gets.upcase
b=gets.upcase
p (b*2).include? a
With the examples I can think of, the Ruby code works correctly, but for some reason, it didn't work on the code golf site (codingame.com, the problem was proposed by user "10100111001").
In Ruby gets includes the \n at the end. You'd have to .chomp it away before doing anything.
a=gets.chomp.upcase
b=gets.chomp.upcase
p (b*2).include? a
By the way, this is not the right way to "tell whether it was possible to obtain one string by rotating the other string", it only partially solves the problem, hope you know that.
I'm looking for some help understanding why I get an error (no implicit conversion of nil into String) when attempting to use a for-loop to search through an array of letters (and add them to a resulting string, which seems to be the real problem), but not when I use a while-loop or 'each' for the same purposes. I've looked through a lot of documentation, but haven't been able to find an answer as to why this is happening. I understand that I could just use the "each" method and call it a day, but I'd prefer to comprehend the cause as well as the effect (and hopefully avoid this problem in the future).
The following method works as desired: printing "result" which is the original string, only with "!" in place of any vowels.
s="helloHELLO"
result=""
vowels=["a","e","i","o","u","A","E","I","O","U"]
string_array=s.split("")
string_array.each do |i|
if vowels.include?(i)
result+="!"
else
result+=i
end
end
puts result
However, my initial attempt (posted below) raises the error mentioned above: "no implicit conversion of nil into String" citing lines 5 and 9.
s="helloHELLO"
result=""
vowels=["a","e","i","o","u","A","E","I","O","U"]
string_array=s.split("")
for i in 0..string_array.length
if vowels.include?(string_array[i])
result+= "!"
else
result+=string_array[i]
end
end
puts result
Through experimentation, I managed to get it working; and I determined--through printing to screen rather than storing in "result"--that the problem occurs during concatenation of the target letter to the string "result". But why is "string_array[i]" (line #9) seen as NIL rather than as a String? I feel like I'm missing something very obvious.
If it matters: This is just a kata on CodeWars that lead me to a fundamental question about data types and the mechanics of the for..in loop. This seemed very relevant, but not 100% on the mark for my question: "for" vs "each" in Ruby.
Thanks in advance for the help.
EDIT:
Okay, I think I figured it out. I'd still love some answers though, to confirm, clarify, or downright refute.
I realized that if I wanted to use the for-loop, I should use the array itself as the "range" rather than "0..array.length", like so:
s="helloHELLO"
result=""
vowels=["a","e","i","o","u","A","E","I","O","U"]
string_array=s.split("")
for i in string_array
if vowels.include?(i)
result+= "!"
else
result+=i
end
end
puts result
So, is it that since the "each" method variable (in this case, "i") doesn't exist outside the scope of the main block, its datatype become nil after evaluating whether it's included in the 'vowels' array?
You got beaten by the classical error when iterating an array starting with index 0, instead of length as end position it should be length-1.
But it seems like you come from some other programming language, your code is not Rubyesque, a 'For' for example is seldom used.
Ruby is a higher language than most others, it has many solutions build in, we call it 'sugared' because Ruby is meant to make us programmers happy. What you try to achieve can be done in just one line.
"helloHELLO".scan(/[aeoui]/i).count
Some explanation: the literal array "hello HELLO" is a String, meaning an object of the String class and as such has a lot of methods you can use, like scan, which scans the string for the regular expression /[aeoui]/ which means any of the characters enclosed in the [], the i at the end makes it case insentitive so you don't have to add AEOUI. The scan returns an array with the matching characters, an object of the Array class has the method count, which gives us the ... Yeah once you get the drift it's easy, you can string together methods which act upon each other.
Your for loop:
for i in 0..string_array.length
loops from 0 to 10.
But string[10] #=> nil because there is no element at index 10. And then on line 9 you try to add nil to result
result = result + string_array[i] #expanded
You can't add nil to a string like this, you have to convert nil to a string explicitly thus the error. The best way to fix this issue is to change your for loop to:
for i in 0..string_array.length-1
Then your loop will finish at the last element, string[9].
I have limited knowledge of lua and would like to make an or statement.
However, I don't know the exact syntax.
Would the code below work correctly?
if text == "/teamspeak" or text == "/ts" then
If not please let me know on the correct syntax of the statement.
Yes, the statements are correct. You do not have any syntactical errors there, though you might want to check whether text contains only the command or the whole string (as is the case with ptokax). You might also want to check that the command is uppercase/lowercase or mixed-casing.
local sCmd = text:lower()
if sCmd == "/ts" or sCmd == "/teamspeak" then
...
end
Lua uses the keyword or for or statements.
I recommend reading the Lua language reference.
Your code would work correctly if you terminate the if then statement with end.
Best way is to try it yourself. If you do not have Lua installed you can use http://www.lua.org/demo.html
And please note that nil is not the same as false! Many Lua beginners have problems here.
That statement should work, though I suggest converting the string to lowercase first, as jhpotter92 already suggested.
A typical problem in cases like this is when the order the language deals with operands is not the one you'd expect; if, for example, lua were to evaluate the or before the == operator (which it doesn't, see reference) that code would not work. Therefore it is never a bad idea to write your code like this
if (text == "/teamspeak") or (text = "/ts") then <...> end
just to be sure lua does things in the correct order.
If you ever find yourself in this kind of situation again, and you don't want to wait for someone to respond to your question, you can just start lua in interactive mode (assuming you have lua installed on your system, which is very helpful for everyone who wants to learn/code in lua) and type something like
> text = "/teamspeak"
> if text == "/teamspeak" or text == "/ts" then print "true ♥" end
In this example, the console will output "true ♥". Repeat this with text="/ts" and text="some other string" and see if the line of code behaves as it should.
This shouldn't take you longer than 5 minutes (maybe +5 minutes to install lua first)
This question already has answers here:
Kernel#gets attempts to read file instead of standard input
(2 answers)
Closed 10 years ago.
If I hard code the variable max below, my program runs with no problems. If I pass an argument in, max sets correctly but gets throws and error. Why is that?
max = ARGV[0].to_i
# Ask user for first guess
puts "I am thinking of a number between 1 and " + max.to_s + "."
print "Make your guess: "
guess = gets.chomp.to_i
Error Thrown: `gets': No such file or directory (Errno:: ENOENT)
Note: The error is fixed by changing gets to STDIN.gets but why is this needed when without the argument my program works fine?
Further, is there a way to change the default behavior of gets back to STDIN.gets for the entire file? Perhaps with one line at the top of the program?
Kernel.gets has some interesting behavior that explains your issue:
http://www.ruby-doc.org/core-1.9.3/Kernel.html#method-i-gets
Specifically, it behaves differently depending on whether or not ARGV is empty, and if it is not empty then it will behave differently from STDIN.gets. If you don't want to use STDIN.gets explicitly, you might use max = ARGV.shift to remove that element before calling gets.
Addressing your last question: the best way to force gets' behavior to match STDIN.gets is probably to make sure ARGV is empty before doing anything else, and to make sure it stays that way. However, it may be wiser to continue to simply use STDIN.gets, "just to be sure". In cases like this, where unusual and surprising behavior is possible, it is almost always best to write code as explicitly as possible.
You should use:
STDIN.gets
When trying to get user input.
this is my first post here. I started using Ruby just 2 days ago and think it is an amazing language, however I have been getting stuck. My problem is I am wanting to calculate the event horizon of a black hole given an input defined in the code as "m" This will then be put into a calculation and the size then printed out to the screen. I did need it to be in binary and thats where I am having the issue.
Here is my code so far.
#Event Horizon Calculation Program
G = 6.67*10**-11
m = 20
C = 200000
R = G*m/(C**2)
puts "Here is the result in Binary."
R.to_i(2)
puts R
Now I do realise that the number are not accurate, that dosen't matter at the moment. I just need the function to work.
Thankyou,
Ross.
Your post is not even in a format of asking a question, but guessing from what you wrote, it seems that you are asking how to change your code so that it accepts an input to m and outputs the result. My answer is based on this assumption.
In order to take an input, use the 'gets' method. So, you may want to replace your 'm = 20' line with:
m = gets.to_f
'gets' accepts an input as a string, so you need to convert it to a numeric. to_f changes a string into a float. You can use to_i instead if you want an integer.
You have a line 'R.to_i(2)', and it seems like you want to output this, but you have two problems here. First of all, whatever that creates, it is only creating something in that position, and does not change the value of R, so, in effect, it actually does nothing. Second, ruby can accept numerals in source code written in different bases such decimal, binary, hex, etc., but it only has one internal representation, and you cannot output a numeral in binary. For your purpose, you need to convert it to a string that corresponds to a binary expression. For that, use the 'to_s' method. In fact, the 'to_i' method does not take an argument. Delete your line 'R.to_i(s)', and replace the line 'puts R' with:
puts R.to_s(2)