Opening Python script mode on a MacBook - python

I have a MacBook air and have tried opening Python in terminal but when I open it, it opens Python interactive mode. Does anyone know how to open Python script mode please.
I’ve tried typing in things such as Python or Python 3 like safari suggests but that didn’t work.

There is no 'script mode'. You can create a Python script using TextEdit or another editor, save it as myfile.py, and then run it with python myfile.py.

for running what you are calling 'script version' of python you should choose a python file to run and make sure is written in the same or in a compatible version to the python you are running it with (python2, python3)
For running an example script:
python main.py
You need to be in the directory containing the file so make sure you are there before running the command. Using python runs the first version of python you installed, so if you want to use an other you should use:
python2 main.py
python3 main.py
etc

Assuming you've stored your script in a file named itworks.py, the simplest thing is to type the command python3 itworks.py in a terminal window after you've moved to the directory containing the script. Alternatively, you can type python3 followed by a space, then locate your python script in the Finder and drag and drop it into the terminal. This will expand to the full path to the file, allowing you to run a script located elsewhere than your current directory. Don't forget to press return...
In older versions of MacOS you could say python, but that uses python 2 which is no longer supported so you should go with python3 for any new development. (With MacOS Ventura, python 2 seems to have been removed.)
If you have multiple versions of python, you can use the command which -a python3 (or python) to see all versions on your PATH, and the order in which they will be found. PATH works on a first-come-first-served basis, but you can override by using the fully qualified path name to an alternative python.
Yet another solution, for when you want a more permanent script you will use many times in the future, is to use a "shebang" line as the first line of your script. For example, I wrote the following tiny demo:
#!/usr/bin/env python3
print('It works!')
The first line says to parse this script with the first python3 interpreter found in your current environment's PATH. You could replace that with an explicit path such as #!/opt/homebrew/bin/python3. Now make the script executable: chmod a+x itworks.py. You can now run the script from the current directory by typing ./itworks.py. (The leading ./ tells your shell you know it's in the current directory, and is intended as protection against trojan horse scripts.) If you want to be able to use the now-executable script from anywhere, add it to a directory on your path such as /usr/local/bin, and you'll be able to run it by just typing itworks.py.

Related

Trying to run Python program from command prompt

Path must be messed up and I can't fix it.
In the command prompt I am trying to open and run a python program that I made in IDLE. I am running Python 3.8.5. According to Automate the Boring Stuff, I should just be able to do:
py birthdays.py
But when I do that I get:
C:\Users\name\AppData\Local\Programs\Python\Python38-32\python.exe: can't open file 'birtdays.py': [Errno 2] No such file or directory
All of my scripts are located in: C:\Users\henri\AppData\Local\Programs\Python\Python38-32.
The only thing that I could think of is that it is going one step too far and searching in python.exe instead of just Python38-32. But Ii'm not even sure it works like that.
I tried to add the exact path using:
set PATH=%PATH%;C:\Users\name\AppData\Local\Programs\Python\Python38-32
But when I do this and press enter nothing happens.
when I want to use CMD to run python scripts, I just use
cd\
to back the main root of drive C. then use
cd folderAddress
for several time until to reach the exact scrip containing folder. Finally, I type
python scriptName.py
In your command prompt type python.The output should be python 3.** (depending on your python version).
If you see the python version it's working fine. In command prompt navigate to the folder that you have your python file using cmd command. then type
python birtdays.py
Don't forget the space after python.

Other than swapping order of paths to python folders in system variable 'PATH' - what are the ways to swap python versions?

I can change the order to python2,3 folders in the system PATH variable. But what are other ways to do this?
There should be more elegant way to change versions of python i want to run.
e.g. in console:
python file.py #will run python2
and after i change python command to use python3, it should be the same:
python file.py #will use python3
I suppose you are trying to run your script with the correct interpreter depending on which python version was used. On Unix/Linux this is done with a so called “shebang” which is written in the very first line of the file. E.g.:
#!/usr/bin/env python3.6
If your installation of Python3 is newer than Python 3.3 you can use the python launcher for windows, which should be able to launch the correct version of Python depending on the shebang, even on window.
Also see here for more informations on shebangs.
If your concern is what Python version is executed when calling python in a console, then an alias or a stub script are the two ways to go.
This post will explain you how you can do this on Windows.
The alias way, just like it would be on a Unix system, is to create an alias, either temporary to the session or permanent, so that python now means C:\Python27\python, or whatever version you want.
The script approach consists in putting a script named python in a directory referred to in your PATH, and have that script run the right version of Python.
I highly doubt that this will affect all the batch scripts that call python, but it will definitely fire the right Python when you'll type python in a console.
Now, if you're concerned about what version a script is executed with, you can specify an explicit version with a shebang line, or manually select it by right-clicking the .py file and clicking open with.

Running a python program after setting the execute bit in Python 3

I was going through Google's Python instructions and it quotes:
The commands above are the simplest way to run python programs. If the
"execute bit" is set on a .py file, it can be run by name without
having to type "python" first. Set the execute bit with the "chmod"
command like this:
Where it proceeds to give me this code to run on my terminal:
~/google-python-exercises$ chmod +x hello.py
~/google-python-exercises$ ./hello.py ## now can run it as ./hello.py
Hello World
However when I type in ./hello.py, I get:
So is this something to do with me using Python 3 when this could be a command for Python 2?
EDIT
I just realised that this can only be run on a Linux/Mac. How does one go about doing this on a Windows?
You need to associate the file extension with Python properly. This should happen by default if you install system wide (which requires administrator privileges), but if you're using a third party distribution, it's not guaranteed, and it may require a reboot even so.
For more details running Python on Windows, see the Python on Windows docs. It looks like if you omitted the launcher from your Python install, it won't have registered the file extensions; it may be worth reinstalling properly to fix that.
Otherwise, if you can't get file extension associations working, just run:
python hello.py
or starting with 3.3 and later, you can use:
py hello.py
which lets you provide an argument to py.exe to change which installed version of Python to use (if desired).
You wouldn't use ./hello.py on Windows at all, because that's the wrong directory separator (Windows sometimes allows forward slashes, but in DOS prompts, that looks like trying to launch a program named . with the switch /hello.py). You'd use plain hello.py (Windows always searches the current working directory) or .\hello.py if you want to be explicit.
Do you have a shebang as the first line in hello.py?
something like:
#!/usr/bin/env python3

Is there a way to shorten command line commands to open Python scripts?

I'd like to know if there is a way to shorten what must be written on the cmd.exe command line to run Python programs. As it is, I have a program called Calculator.py and if I wanted to run that I would have to write:
python.exe C:\Users\user_name\restofdirectory\Calculator.py
Basically I want to know if I could make the 'Python' folder on my computer default so I could just type python.exe Calculator.py or some other similarly short way of doing it so I didn't have to type the whole directory.
Create a cmd.exe shortcut somewhere handy (Desktop or whatever). Right Click, select properties. Under the Shortcut tab you'll have a "Start In" field. It'll be default to wherever your cmd.exe normally opens. But you can change it to any path you want (So set it to your python development folder)-- then opening that shortcut will always start cmd.exe in the python folder.
You don't need to type python.exe file.py --
Just type: python file.py
So in short, you'd click that shortcut and type python file.py and you are done.
If you have specific scripts you want to run frequently, you can create a cmd.exe shortcut for each one. Set the Start In path to their folder. Then update the link to cmd.exe like this:
c:\path\to\cmd.exe /k python file.py
That will open a cmd prompt and automatically run that specific script
Yes, you can cd into the folder first.
If python is in your default path you can create a folder and put all your python scripts in it. Then cd into that folder and type python Calculator.py. To test if python is in your path simply open up a cmd and type cd \ (which in your case should change your working directory to C:\) then type python. If you get an error saying the command python cannot be found then you have to add python to your path. Other wise you should be able to run cd C:\Users\user_name\restofdirectory\ and then execute the script python Calculator.py
create an environment variable, say, PyPath = C:\Users\user_name\restofdirectory
then your line would be:
python.exe %PyPath%\Calculator.py
or you just cd to C:\Users\user_name\restofdirectory, and run
python.exe Calculator.py
Add Python to your path:
SET PATH=%PATH%;C:\Python27\bin
then you can call python like this:
python myapp.py
If you have the Python Launcher for Windows (comes with Python 3.3+) installed, then it gets even easier. You just need to put shebang in your code:
#! python
The first time you run your code, Windows will pop up a dialog and ask you what program to use to run the script. The Python Launcher should be listed. Just choose that and away you go. Here's a fun little script from the page I linked earlier:
#! python
import sys
sys.stdout.write("hello from Python %s\n" % (sys.version,))
Once my Windows 7 box had the launcher installed and I told it what program to run, I could just call my script from cmd.exe like this:
my_script.py
Note: If you have a version of Python older than 3.3, you can download the installer here

Python Beginner: ImportError when run from NP++ but not IDLE

I am using Python 3.3 (2.7 is also installed) and a compatible version of pygame. Recently I have been trying to switch from IDLE to Notepad++
I am using a saved shortcut in Notepad++
C:\Python33\python.bat "$(CURRENT_DIRECTORY)" "$(FILE_NAME)"
which runs the batch file:
#echo off
cd %1
%2
if not errorlevel 1 goto quit
echo.
echo.
pause
:quit
When I run C:\Python33\Foldername\imp_prob.py
import pygame
in IDLE it works fine, in Notepad++ using that shortcut it gives an ImportError: No module named pygame
My questions are:
Why is the NP++ method not producing the same result?
How can I change the shortcut or batch file to make it run stuff that IDLE can run?
What method can I use to ensure that I can import a module regardless of which directory I am running the program from?
edit: a working alternative was in the answers to How do you run a python script from within notepad++?
I had some issues with the code they provided, but replacing "python" with the full path to my python33 install solved that.
I still don't understand why pygame wouldn't import when using my run shortcut. I also don't understand why NppExec works when Run doesn't.
It sounds like you would need to set your systemvariables. Idle does not require these steps. You entered the full path to the python.exe in np++ to execute the python program, but the path to the modules etc. is still unknown.
Add the paths, and try again.
System Properties -> Advanced -> Environment Variables, in the bottom window look for a "Path" variable, Edit and append the following the existing entries (do not delete anything in there!)
;C:\Python33;C:\Python33\DLLs;C:\Python33\Lib
for Python 3.3, if you have installed it into its default directory.
To see if everything worked, open the console anywhere (shift+rightclick -> Open Command Window Here) and just type "python". The python console should open, telling you that you use python 3.3. You then also do not need to tell np++ the full python path, but instead can just use "python" again.

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