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I decided recently that I want to start learning to code. I chose python as my first language because of it's versatility and Open Source connections. Now, of course to learn any programming language, first you have to be able to practice with it by writing code and running it.
I have Python beginner tutorials I am using but as soon as I got to the point where I wanted to run a simple Hello World message, I couldn't figure out how to get my document to actually RUN. I downloaded LiClipse with the hopes of using PyDev. I read that you can run a code directly from PyDev.
Wow, what a confusing mess! I downloaded the instant install version of LiClipse and I had to manually update the pip because it was out of date and that took an hour of research all on it's own to figure out how to do it.
Now that I have the interpreter set up correctly with the most recent pip...(I THINK), when I try to run any code I write, it doesn't let me. It wants me to save it first, which of course is quite logical. But when I try to save it, it says there is no folders to save to. How can there be no folders? I have been reading the install help, but it doesn't say anything about this issue. Or maybe it did explain how to fix this issue and I simply didn't understand all the jargon included in the configuration documentation. It kept instructing me to do technical things I couldn't understand.
Can anyone tell me what is going on? Shouldn't this all be ready to go when I used the "instant install" ?? I am just a beginner here, I don't know all this technical installation jargon. If anyone can help me get this setup, please let me know.
I really want to start learning. But I can't if I don't have the right tools.
Yeah, the technical jargon can be really confusing in the beginning. I've never heard of LiClipse but I can give you a few tips to get started:
Use a good IDE or Editor. For beginning VsCode with the Python PlugIn is quite good. You can also use PyCharm (the free version is enough) but that IDE is quite confusing.
Get comfortable with the commandline. On Windows you can invoke Python by running py on Linux with python3. You open the commandline on Windows by opening the startmenu, entering cmd and hitting enter.
You will have to make sure Python is in your "PATH" enviroment variable. That is a variable telling the Operating System where to find your programms. It should have asked you whether you want to add Python to your PATH during the install.
You run your python programm by saving it as a .py file and running py <filename.py> or python3 <filename.py> on Windows or linux respectively. You have to be in the directory where you saved your file of course.
I hope I could help you. Please mark this answer as accepted if it did answer your question or helped you with your issue.
I want to start by saying I'm mainly experienced in C & C++, not Python, but with programming in general many of the concepts carry over. I also don't have enough rep to comment, or I'd ask for some clarification on how familiar you are with the commandline.
I'm going to assume you're on Windows since you didn't mention the platform.
I wrote this like a tutorial, because I found those to be very helpful when I first started programming.
I can't recommend this enough, start off by using the commandline!
I think you complicated things more by searching for a text editor that can also run code. In order to get something like that working for your setup you need to know what's happening behind-the-scenes first.
Once you have a grasp of how to write & execute Python code, then you can move on to an IDE or advanced text editor like Visual Studio Code or LiClipse with confidence.
R+Click on the Start Menu, then click on Windows PowerShell to open a terminal.
Take a moment to note the filepath shown before the blinking cursor.
This is known as the Working Directory, which works similar to how the file explorer only allows you to "view" one directory at any given time; You can open multiple explorer windows side-by-side, but you can't view multiple directories at the same time in a single window.
You can run commands by typing them and pressing Enter.
You can also use the Tab key to autocomplete things like directory/file names, commands, etc. after typing a few characters.
Now let's create a workspace directory for your first project.
This can be anywhere that you choose, but for the sake of simplicity I'll be using my User directory which is usually where PowerShell will start by default.
To create a new directory named _workspace, use the mkdir (Make Directory) command like so:
mkdir _workspace
Now let's change our working directory to _workspace by using the cd (Change Directory) command like so:
cd _workspace
This directory is empty, but if you want to view the contents of a directory you can use the ls (List Directory) command:
ls
Since this is an empty directory, nothing will happen.
Next, we'll create a Python script file using the touch command, which creates empty files:
touch HelloWorld.py
Now that we have a script file, open HelloWorld.py in Notepad by running this command:
notepad HelloWorld.py
If you use a dark desktop theme, now is the time when your retinas may be seared out by the intensity of Notepad's white color scheme.
Now, let's add the code to print "Hello World!" in Python:
print("Hello World!")
Once you're done, you can save & close Notepad to save your retinas.
Now it's time to run the program! In the PowerShell window, enter this command:
py HelloWorld.py
which will show:
Hello World!
If you see an error saying this:
The term 'py' is not recognized as the name of a cmdlet, function, script file, or operable program.
You should re-install Python and make sure you check this box in the installer:
After re-installing Python and checking the Add to PATH box, close and reopen the PowerShell window, enter the cd _workspace command again, followed by py HelloWorld.py, which should be successful this time.
I hope I could be of some help, if so, I'd greatly appreciate marking this answer as accepted so I can write comments. Happy coding!
If you are using Linux following will work.
Install python3 first (Its better to stuck on python3 now. Once you get use-to then you can code in python2.7 also.)
Open a terminal, go the folder contains your code. If your source code is in hello.py then type python3 hello.py on terminal. It will execute and print the output on terminal.
The suggestions given by both #radj and #C. Dautermann are excellent.
Like others here, I will be assuming that you are on Windows.
Before jumping into LiClipse and PyDev, I highly recommend making sure that Python and packages (such as pip) are functioning on their own first. Command line is a great tool for this.
Windows Command Line can be accessed in a variety of ways, one of which is to go to your start menu and search "cmd." Command Prompt should return. In the command prompt, run the following:
python
This should return the version of Python installed on your machine if it is configured properly. For example, you may see the following:
Python 3.10.1 (...)[...] on win32
If this does not appear, I recommend uninstalling Python and reinstalling. In the installer, you will want to check the "Add Python ... to PATH" option. This will configure your environment variables on your machine. If you plan on running multiple versions of Python down the road, don't worry; you can use batch files to set the PATH variable to another version.
Once you have Python working, your command prompt will lead with the following:
>>>
Notice that there is no longer a file path followed by >>. This is because you are now in the Python interpreter. Congratulations!
To exit the Python interpreter, enter Ctrl+Z. It should appear as the following:
^Z
After we know Python works, we will check to see that pip works. Ensure you have pip installed by entering the following:
python -m pip --version
You should then be able to see the pip version. For example:
pip 22.0.3 from C:\...
If pip is not working, you can consult this documentation on pip to make sure pip gets installed properly.
Once pip is working, again, congratulations! You've gotten over some of the biggest hurdles. At this point, you can open up any text editor, type in:
print('Hello World!')
save the file with the extension .py, then run the script through command prompt. To run a script through the command line, you have to cd to the file location, then run the script with python, like so:
cd filepath
python filename.py
Where filepath is the path to the Python file and filename is the name of the file. For example:
cd C:\Users\name\Documents\PythonPractice
python helloworld.py
Usually, command line is all that is needed when starting out with Python outside of a text editor. Notepad comes standard on Windows computers, but there are plenty of other editors out there. Sublime text and Notepad++ are some of my favorites, personally.
Now, if you're able to run everything prior, the good news is that your Python and pip are both working, and you have everything you need to get started learning Python. If Python and/or pip are not functioning, there's thankfully a huge body of troubleshooting tips out there.
Unfortunately, from what I get of your initial post, you might be struggling with configuring LiClipse. I personally do not use LiClipse, nor do I use PyDev, so my help at this point may be limited. You may want to uninstall and reinstall after confirming your Python and pip work as a first step. After that, perhaps check that you are following the practices outlined in the LiClipse manual. Worst case scenario, you can try a different version of Python (I believe it has some Python3 incompatibilities), try running PyDev independent of LiClipse, or look at a different tool. If you believe the problem lies with file locations/existence, I would look at radj's post or play around in File Explorer to see what is going on for yourself.
Again, to get familiar with Python, you don't even need these extra tools. All you need is a text editor and the command line to get started.
Some other tools to help you get started:
PyPI
A venv virtual environment tutorial
PyDev
A comparison of LiClipse alternatives in case you continue to struggle
Hope this helps. Happy Coding!
Related
pyenv-virtualenv offers a nice way of activating the environment on the very instant of entering or leaving the directory which contains a .python-version text file which specifies the environment to activate. It works for the directory it is in and all directories contained in it.
The environment is deactivated once we change the directory to something above it. This allows to easily switch between projects or analyses using different python versions (just by changing the directories).
Is there a way of achieving the same behaviour with (ana)conda?
Edit: added bash tag, because - as far as I understand - pyenv achieves this by hooking a custom script into .bashrc (which allows it to monitor the directory changes). If there is no build-in way in conda, how to create a script which would make it possible?
As mentioned in my comment, this is currently not supported. There is however an open issue on conda's GitHub asking for this feature.
In the meantime you could use autoenv, a small tool that'll automatically run the code in a .env file when entering a directory and that in a .env.leave when leaving the directory (supports bash/zsh and a couple others).
A simple example taken from their readme which illustrates the feature quite nicely:
$ echo "echo 'whoa'" > project/.env
$ cd project
whoa
To load a conda environment your .env would simply look like this:
conda activate <my_env>
Note 1: Check out the Configuration section of their GitHub readme before you start using it.
Note 2: The author of autoenv actually suggests trying direnv instead. However I've never used it, so I can't comment on it.
From autoenv's readme:
you should probably use direnv instead. Simply put, it is higher quality software. But, autoenv is still great, too. Maybe try both? :)
Web development is new to me and I'm trying to grasp the meaning and usage of environment variables once and for all. In my research the most simple explanation I've come across is that it is comparable to 'configuration settings'.
Through the terminal I've been exploring what feels like the computer's innards by typing printenv etc etc.
But I'm still not sure when it is necessary to set up env var. For example, I use fish as my shell. Often when I try to do an npm install it seems like the package didn't take. Here is a recent example:
user#iMac-van-user ~/P/v/v/public_html> npm install -g modernizr
/usr/local/Cellar/node/10.4.0/bin/modernizr -> /usr/local/Cellar/node/10.4.0/lib/node_modules/modernizr/bin/modernizr
+ modernizr#3.6.0
updated 1 package in 2.316s
user#iMac-van-user ~/P/v/v/public_html> modernizr
When I try to use modernizr as a command fish will tell me the modernizr is an unknown command and the color remains red. Valid commands show up in white in fish. Thus I have a suspicion that modernizr will only be available and valid once I've set up the configs. I've had this happen many times with various attempts to install package managers and things like composer, vue-cli, etc. My failures to get it working boils down to my meager knowledge of environment variables and what they do, I think.
This is from the documentation on the modernizr site: modernizr -c modernizr-config.json
Note that you will need to give the command line config the file path
to the configuration you downloaded from the site. In the above
example, we are running the modernizr command from the same folder
that we downloaded the modernizr-config.json file to.
What does the sentence: "Note that you will need to give the command line config the file path to the configuration you downloaded from the site" imply? I copied the file into my project folder but there is no change.
Is there is someone that can explain the following to me in layman's terms, so like you would to a 5 year old, it would be great:
use of environment variables
setting up configs - why, where and how (I've done it once through VIM)
how to know when to set up environment variables
Thank you in advance.
Developing on macOS 10.
Followed the instructions in transcrypt "getting started" docs, I entered the examples 'hello.html' and 'hello.py' in a separate directory.
Entering from the command line: "transcrypt -b -m hello.py" resuleds in the error message: "'transcrypt' is not recognized as an internal or external command,
operable program or batch file."
I'm using python3.6, with transcrypt installed in: C:\program files\python36\lib\site-packages\transcrypt
Any help to activate the sample hello.html would be appreciated.
Could you try python -m transcrypt -b -m hello.py
and tell me what the console output is?
Also: are you on Windows, Linux or OsX?
Answer: Windows 10
[EDIT 1]
Looks like Transcrypt was installed under a different Python distro. Would be good to know what's going on, so please keep us informed. I also have several Python installs on my Windows 10 computer and it can be confusing indeed.
[EDIT 2]
Another possibility is manual installation (although it isn't elegant...). From the docs
http://www.transcrypt.org/docs/html/installation_use.html#installation-troubleshooting-checklist
Alternatively, for manual installation under Windows or Linux, follow
the steps below:
Download the Transcrypt zip and unpack it anywhere you like
Add ../Transcrypt-/transcrypt to your system path
To enable minification, additionally the Java Runtime Environment 6 or later has to be installed
Note If you install Transcrypt manually, Trancrypt is started by typing run_transcrypt rather than transcrypt. This allows a pip
installed Transcrypt and a manually installed Transcrypt to be used
side by side selectively
BTW Thanks for the suggestion on Github. We'll look into it and try to improve the docs on this point. It seems to be quite difficult to really draw up a bullet proof installation procedure for each platform.
You might also find it easier to use python3's built in virtual env, so that you install Transcrypt and other python modules only into one project folder at a time. It's much easier to use than it at first sounds.
Here's how you might do that on Windows 10.
mkdir mynewproject
cd mynewproject
py -3 -m venv myvirtualenv # installs venv files into myvirtualenv
myvirtualenv\Scripts\activate # activates the virtual env
The py -3 command uses the python windows launcher to use the latest version of python 3. The launcher is defined in Pep 397 and the docs are here.
Once the virtual environment is activated, the prompt will change to show that. After which any 'pip install' commands will install packages into 'myvirtualenv', instead of the system wide location. If you want to deactivate it, just type 'deactivate' or close the shell window. You can also just use 'python' to refer to python3 from within the virtual env. This has saved many people from madness.
In case this helps for other newbies. A few problems I encountered when setting up transcrypt.
Path issues: I had multiple versions of python, in different folders: \python26, \python27, and \Program Files\python36.
This caused all sorts of grief, despite setting the environmental path to include the python36 distro. I fixed this issue by renaming the other versions \python26x and \python27x. This left those distros intact if ever I needed to use them, but stopped the system from finding them. Thus, it only found python36
My earlier suggestion of py -3 didn't really solve the multiple distro issue completely after all.
After doing that, I reinstalled transcrypt and it seemed OK (sort of: read on)
Second issue was trying to run the sample hello.py. I tried "transcrypt -b hello.py" and got a "'transcrypt' is not recognized.." message.
But this worked: python -m transcrypt -b -m hello.py
That worked because the system had finally found the correct version of python, due to the above fix.
Similarly, trying to run the sample hello.py as recommended in the docs caused a problem. run_transcrypt -b hello.py
The reason for this was that run_transcrypt resolved to "python $(dirname $0)/main.py $*"
But, because I had python v3.6 installed in c:\Program Files, the batch file run_transcrypt caused this output:
c:\transcrypt>python C:\Program Files\Python36\Lib\site-packages\transcrypt__main__.py -b hello.py
python: can't open file 'C:\Program': [Errno 2] No such file or directory
Consequently, I had to place Program Files in quotes and run it this way:
"C:\Program Files"\Python36\Lib\site-packages\transcrypt__main__.py -b hello.py
or else, as above: python -m transcrypt -b -m hello.py
I think, with respect, the docs should raise a warning flag here for users who have python installed in \Program Files, rather than, for example, in c:\python[x]
Third issue Changing hello.py to "play around" with the code -
I found the files in transcrypt\demos\ to be read-only. To fix this:
1: I opened the command prompt as administrator
2: I ran the attrib command to change the file attributes:
"c:\Program Files\Python36\Lib\site-packages\transcrypt\demos\hello>attrib -r -s -a hello.py"
(Without doing this as administrator you get an access-denied message)
The whole exercise caused a few hours of toing and froing, but it seems that things are better now.
I'm trying to use mongodb on my Mac for a nodeJS app. I followed the steps given here to install mongo.
First of all, I wanted to know if adding mongodb path to the PATH with "nano .profile", or with "vim .bash_profile" is the same ? I'm used to using "nano .profile" and I want to know what are the differences.
Then, I added the path to mongodb in the .profile but when I try to use the command "mongo", it tells me "command not found". Although, when I manually type /usr/local/mongodb/bin/mongo (which is the path that I added in .profile), it works. I don't understand what's going on and the only solutions I find on the Internet are modifying the .profile, but mine seems correct to me.
Thanks for you help.
Mat
I want to know what are the differences.
Do a web search for ".bash_profile .profile". Stackoverflow's guidelines require "thoroughly researched" questions. There are countless detailed articles on this topic.
To get things working try typing exec $SHELL to reload your shell. If your PATH is correctly set up, typing mongo should work. Another command to be aware of is rehash which you need when you add a new program to an existing directory on your PATH because the shell basically scans the entire PATH and makes a lookup table, but when a new command program gets installed after that, the shell doesn't automatically notice. That's what rehash is for.
I was wondering if the following is possible.
I have a BASH script that I want to make available for some people but I wanted them to only have to "install" the program and not messing around with terminal, so I thought a .deb would be cool.
So what would the "install" do?
Simple. I want to move the script and an icon to a folder (any folder, but I was wondering some hidden folder in Home) and then run a script that creates a launcher in the Applications menu for the first script. It seems there isn't much to it, but for what I've searched, there doesn't seem to be a lot of info...
How can I accomplish this?
By the way, I'm using Ubuntu 11.04.
Basically (install and) run dh-make to set up the debian/ directory, edit the generated files (mainly remove the many you do not need, and fill in a package description and any dependencies in debian/control), then debuild-us -uc -b.
You may also have to set up a simple Makefile for debian/rules to call; it probably only needs an install target to copy the binary to $(DESTDIR)/usr/bin.
Binaries install into /usr/bin and you should not try to override that. The way to have a menu is to add a .desktop file.
Once you have a good .deb you will need to set up a repo for distributing it. The simplest solution is probably to set up a launchpad.net account and create a personal PPA there.
It's not hard to find more information on these topics, but of course, you need to know what to look for. The canonical documentation is the Debian New Maintainer's Guide.
Found this video on youtube that explains IN FULL the process of creating a *.deb for a script or program and even mentions how to do it for a C program.
Full guide in how to build simple *.deb package
Has one bug, btw, that the author, during the making of the *.deb, didn't notice. The path in the *.desktop file for the EXEC parameter is wrong in the example.