Could you tell me what is difference between execfile and subprocess . I guess these two commands work same .
but when I use Execfile() there is no problem getting variable from another .py file . but when I try to use subprocess.Popen() there is an error like ""NameError: global name 'xy' is not defined""
what provide to get that error ? and why when I use Popen command that gives error and execfile works fine ..
execfile and popen are very different commands.
Execfile allows to to pull in another file of python and run it in the same environment as your main script.
Popen allows you to spawn a subprocess of anything you like, not just python. It's a 'blackbox' so your chances of seeing what's happening in it is limited to the exit value it posts, or scanning it's STDERR and STDOUT
If you really want to run your second script standalone use popen)
If you want to import your other python code and embed it in your file (use execfile, if you must).
Related
I'm following along with Google's Python class, and the person in the videos always runs his scripts from the interactive session in command line using "./". Whenever I try it, I just get a syntax error. How can I use ./ to run scripts? I'm using Windows 10
To run a script from the command line you need to use the syntax
python3 script.py
Now on Unix systems, it's possible to add a shebang to the first line of the script as followings
#!/usr/bin/env python3
This then allows the shell syntax './name.py' to work. But windows doesn't have this mechanism. Instead, you need to create an 'association' between the .py extension and the python executable ('right click', 'open with'). Or just use the full syntax. Both require the python executable to be in your path, and generally on windows both python 2 and 3 will have the same executable name
I have been trying enter couple of commands on a command window with python script. I was able to open the .exe file by checking the other questions.
However, now my code:
import os
os.chdir(r'filepath')
os.system("start /B start filepath\application.exe")
opens the application and it asks for an input file name, then it will ask for output file name. Is there a way to do that. This will be used for ArcGIS so it needs to be done in python 2.7.
I checked all related questions but did not find the answer. I would appreciate it very much if you could help.
Finally! It was easier than I thought but I needed lots of research. This code for python 2.7 which may differ for other versions.
import os
import subprocess
os.chdir(r'filepath')
subprocess.check_call([r"filepath\your_.exe_app", 'your_input'])
I am running an executable from cmd:
*.exe input.inp
I want to run it using python and tried following:
os.system('"*.exe"')
But don't know how to specify input file as well. Any suggestions?
import os
from subprocess import Popen, PIPE
p = Popen('fortranExecutable', stdin=PIPE) #NOTE: no shell=True here
p.communicate(os.linesep.join(["input 1", "input 2"]))
For more please refer to:
Using Python to run executable and fill in user input
I had to launch cmd window and specify input file location from within Python script. This page was really helpful in getting it done.
I used Popen(['cmd', '/K', 'command']) from above page and replaced '/K' with '/C' in it to run and close the cmd window.
import os
os.system(r'pathToExe.exe inputFileOrWhateverOtherCommand')
I am new to python, just got the learning python book and got stuck with the spam.py in the command line. The book says to make a file named spam.py and then ask python to run this by typing
%python spam.py
I have added the python to my PATH as it was C:\Python27 so I can call Python in the Windows CMD, but this just will not run. The error I receive is
>>>python spam.py
File "<stdin>", line 1
python spam.py
^
SyntaxError: invalid syntax
I appreciate any help that you can give.
Your problem is that you're trying to run your code from within the Python interpreter itself (the >>> prompt is the giveaway here since that's the Python prompt).
Exit from the interpreter (with CTRL-Z and ENTER for Windows) and run it from cmd.exe (the c:\> is the prompt in the example below):
c:\> python spam.py
From within the interpreter, you can also run an external file with:
execfile('spam.py')
Could you post the code from spam.py...
You seem to be trying to run the spam.py from the Python interpreter. Go to where the file is in Windows Explorer and launch it from there, using the C:\Python2.7\python.exe CLI.
By the way, since you didn't understand the syntax error warning, please see:
http://dictionary.reference.com/browse/SYNTAX
http://dictionary.reference.com/browse/SEMANTICS
You are trying to execute Python script file within the interpreter. Come out from the Python interpreter by pressing CTRL+Z and then ENTER key.
Then execute with the command :
Say, C:/> python spam.py
In order to run a python program you have to run program in Command Line not in Python Interpreter (press Windows Sign + R and type cmd.exe)
Moreover you have to remember to be exactly in the directory where your file is saved, e.g.:
If the file file is C:\Python27\spam.py you have to be in C:\Python27.
To change the directory:
use dir to display the folders and files in current place
use cd to change your directory (e.g. C:\Python27\>cd Spam moves you to C:\Python27\Spam
use Tab key to autocomplete names of the commands, folders and files
As you said you have added Python to PATH and followed my instructions, the statement below should work perfectly
python spam.py
Hope I could help.
If for example, your file is in G: drive, type this in cmd:
python G:/myfile.py
Basically, type in the path. Just doing "cd" won't work in Python
I am trying to run my celcius.py file but I don't know what to type in the command line...
When I type Python celcius.py it does not work:
I get the following message:
>>> python celcius.py
File "<stdin>", line 1
python celcius.py
^
SyntaxError: invalid syntax
>>>
When I open it the program with the Python IDLE GUI it runs the program and closes the program before I can see it. I read somewhere that it won't close if you run it from the command line.
You need to type "python celsius.py" in the windows command prompt, rather than the Python command prompt; this only works straight away if the Python directory is in your PATH. It probably isn't, so you need to use this instead: C:\Python27\python.exe celsius.py.
Because celsius for you is in the same folder as python, you can do this as well:
CD C:\Python27
python.exe celsius.py
In general, change the directory (CD) to where your file is stored, then run C:\Python27\python.exe <filename>
Double-clicking is generally easier in Windows, though, assuming it is set up to do that (it normally is unless you change it back)
There are a few ways of doing this.
WAY 1
step one: Open command prompt (go to start and type in "cmd") *NOTE: do NOT open python. if you see ">>>" in your command prompt window you opened python. This is bad.
step two: type in this: python "path\to\file\celcius.py" replacing path\to\file with the path (starting with the name of the folder that you're computer user is named. So for my computer that would be ben. So let's say my celcius.py is located on the desktop I would run python "Desktop\celcius.py" and hit <.enter.>. It looks like you have celcius.py in your python folder. Don't put it there. that's the system files for python itself. move it to your desktop or your documents folder. By the way, if you have truble using this, make sure you're system is set up to execute the python command. Go here for reference.
WAY 2
assuming you have python associated with the .py file in explorer, you can find the file and double-click on it.
WAY 3
open IDLE (you can usually find it in your list of programs in start). Open the python file through IDLE. This will show you the source code for your program. hit <.F5.>. F5 will execute the program from within the the IDLE shell.
You don't need to do this, just open the command prompt and type:
python path/to/your/file.py
Just make sure that python command is set in your environment PATH, check this