The python3 version is Python 3.5.3 in my os.
mkdir workspace
cd workspace
vim print.py
print("i am learning")
Saved and exit.
python3 print.py
i am learning
As far as i knew, python source file was parsed and compiled into pyc file when to execute it.
ls
print.py
There is no pyc file in workspace directory,where is the complied print.py file then?
sudo find / -name ".pyc"
The find command still can't search pyc file such as print.pyc .
python3 -m compileall can create the compiled file for print.py manually,where is the compiled file for print.py created by python itself?
Does python3 delete the print.pyc after executing python3 print.py?
Ok this is one big of a problem I ever had when I'm started to learn python few years back. Python is just like any other oop programming languages which does compilation before program execution. When python compiles its program, it creates the bite code which is you can see by standard library called dis.
import dis
print(dis.dis(your_program))
Sometimes (not always) python creates .pyc file for the running programs to improve the speed up the loading of import modules but not to improve the execution time. So hope you get intuition behind .pyc, furthermore .pyc only creates when your module is import by another module.
As an example, Imagine you have this print.py (Let's modify it shall we)
def return_print_statment(statement):
print('Printed version: ', statement)
Suppose this module imported by another custom module called views.py. In views.py there is a module_view which will use the return_print_statment
from print import return_print_statment
def module_view():
...
return_print_statment(output)
So in the compilation, since you have imported the print.py python will generate print.pyc file for it. In python 2.0 python will put the .pyc to right next to your program in the same folder, but in python3 instead of creating in the same folder python will create separate folder called __pycache__ in the same directory to put these byte codes.
python3 -m compileall .
To compile all .py files in your current directory.
http://effbot.org/pyfaq/how-do-i-create-a-pyc-file.htm
Related
I have written a "random movie suggester" code that will basically read the files of the directory where the .py file is stored and randomly pick one of them and print it out.
My problem is -
How to make .py file simple to run for non-technical person?
(e.g. I tried .bat but i had to hard code the path of the file).
Other solutions ask to install IDEs and run it.
First you have to install python on your computer.
Then you can type in your terminal:
python [the file name or the path to access it]
But I don't think this is what you are looking for...
You can create a .exe file with your python program using the pyinstaller module then running this in your terminal.
pip pyinstaller
pyinstaller --onefile [the name of the file]
The first line installs the module using pip.
The second line will create a .exe file that does exactly the same as your python code.
So I builded a python package localy:
cgi#cgires:~$ pip list | grep mads
madscgi 0.1.0
Its nice! Afterwards I can use it in Jupyter Notebook, in iPython Shell, in Python Shell and even in python scripts outside the modules code. So it works as expected 100% outside the modules code:
Thats nice, but next I want to import code from one builded module (inside the package) into another python file (inside the package). Lets name it import_test.py and try it out:
So it fails if it is getting executed in the directory, where the package is build from. And it looks like, that the python interpreter is taking the parent directory (with the same name like the module) and this is failing.
Is is possible to enforce the usage of the installed pip-package?
As #MisterMiyagi pointed out, the problem was, that there were an upper folder which had the same name as the module.
Here: mads_cons is the upper folder from import_test.py. Therefore, the upper folder is getting imported instead of the via pip installed module. Thats it.
The file you want to import should either be in the same folder or referred to with the absolute path of it.
If that doesn't suit you, you can call sys.path
import sys
sys.path
You can keep your file in any of the directories sys.path returns.
Smart would be, if you keep the file inside.
......../site-packages/
I generally like to make my python programs in a text editor and then run them after they are complete instead of line arguments. Thus, I save those .py files on a convenient folder location instead of Python program files.
I then run my .py file using Command Prompt. However it has not worked for the Biopython library as import Bio gives back a Traceback No module named 'Bio'. However, using line arguments directly on python shows it is installed.
I have never had this issue with Python in general and other downloaded libraries (import numpy for example works fine). How do I make the files available to be open from any location?? Or how do I provide the path in import?
To clarify and add:
1) I use Python from Windows 10
2) I downloaded and installed Python(3.7) from python.com
3) I downloaded Biopython using pip (and all other libraries I downloaded)
4) I also tried it on Jupyter notebook and also does not work to import Bio, whereas Import numpy does.
Thanks!
I'm still a newbie at bash programming, but trying to run a program with little script. Reducing the problem to the error message, I have
cd /full/path/to/program
python3 -m krop
that is the command working when the actual folder is the /full/path/to/program
but if I run the same from root it doesn't work.
cd /another/path
python3 -m /full/path/to/program/krop
/usr/bin/python3: Error while finding module specification for '/full/path/to/program/krop'
(ModuleNotFoundError: No module named 'krop-0')
I tried lot of variants, but always the same output with errors. I do not have a clue of why the library "python3" adds the "-0" at the end of the name of the file.
What should I put to run the program from root?
python -m command expects a module name, similarly to the syntax you would import in a python program. So if your modules lies in ./directory and directory is a valid python module, you can do python -m directory.krop
You can't however index python modules from file system root. You have either to make your bash script run it in the good directory so you make a local import; or you have to package and install your module system-wide to make a global import that would be invoked with python -m krop from anywhere.
More information on packaging and installing modules: https://packaging.python.org/tutorials/packaging-projects/
Problem solved!,
It was a matter of managing the python import paths, as #hiroprotagonist replied. The list that contains all of directories python will use to search for modules, is available in a variable named sys.path.
So, if somebody wants to run a program (a 'library module as a script', according to python help) through python's command, from a directory different from the 'pwd' one, should write in the command line:
export PYTHONPATH='/full/path/to/program/'
python3 -c "import sys; print(sys.path)"
python3 -m krop
The second line is actually to print on screen, but the first one is the only necessary (export PYTHONPATH).
Thank you for the keywords and help!
Ps. May be should be edited the question title to "problem with a python command to run a program from command line on linux" or something like that.
Reference: python --help :)
Is it possible to create a Python Executable file (using PyInstaller or similar) that can in its code access other Python-files stored in a specific folder?
The reason for that it MUST be an Executable is that the script sometimes must be run from computers that has not it's own Python installed. I have no problem creating an executable (with PyInstaller for example) and they work fine. The python script itself loads various kinds of data into a database. But everytime there is a new kind of data that has to be loaded into the database I have to recreate the hole exe-file. I'm looking for a way for the executable to access python-files (with Data Load Instructions) so that the actual pyton load-files can be altered instead of the exe-file.
I have tried to find a solution using this:
import os, time
from subprocess import call
for file in os.listdir('.'):
if file == 'loadInstructions.py':
call(['python', file])
print(file)
cwd = os.getcwd()
print(cwd)
input('To EXIT progran press ENTER.')
time.sleep(3)
It works running it from a python editor but when I turn this into an exe-file it does not. If I creat an exe-file with "call(['python', file])" commented out the rest works which I interpret that the exe-file can find the file in question but not run it.
I would be gratefule for any help.