I am a beginner to python, and I have no idea if this seems to be a doable thing.
I have a simple loop in python that gives me all the files in the current directory.
What I want to do is to execute a C++ code I wrote before on all those files in the directory from python
The proposed python loop should be something like this
import os
for filename in os.listdir(os.getcwd()):
print filename
(Execute the code.cpp on each file with each iteration)
Is there any chance to do this?
Fairly easy to execute an external program from Python - regardless of the language:
import os
import subprocess
for filename in os.listdir(os.getcwd()):
print filename
proc = subprocess.Popen(["./myprog", filename])
proc.wait()
The list used for arguments is platform specific, but it should work OK. You should alter "./myprog" to your own program (it doesn't have to be in the current directory, it will use the PATH environment variable to find it).
Related
This question already has answers here:
Open document with default OS application in Python, both in Windows and Mac OS
(17 answers)
Closed 8 years ago.
I'm wondering how to open files in programs such as Notepad and Picture Viewer depending on the extension the file has. I'm using Python 3.3 on Windows.
I've done some research and people have mentioned a module named Image, but when I try and import this module I get an ImportError.
Here's what I have so far:
def openFile():
fileName = listbox_1.get(ACTIVE)
if fileName.endswith(".jpg"):
fileName.open()
I will also have HTML and JSON files that I will need to open in Notepad.
On Windows you could use os.startfile() to open a file using default application:
import os
os.startfile(filename)
There is no shutil.open() that would do it cross-platform. The close approximation is webbrowser.open():
import webbrowser
webbrowser.open(filename)
that might use automatically open command on OS X, os.startfile() on Windows, xdg-open or similar on Linux.
If you want to run a specific application then you could use subprocess module e.g., Popen() allows to start a program without waiting for it to complete:
import subprocess
p = subprocess.Popen(["notepad.exe", fileName])
# ... do other things while notepad is running
returncode = p.wait() # wait for notepad to exit
There are many ways to use the subprocess module to run programs e.g., subprocess.check_call(command) blocks until the command finishes and raises an exception if the command finishes with a nonzero exit code.
Use this to open any file with the default program:
import os
def openFile():
fileName = listbox_1.get(ACTIVE)
os.system("start " + fileName)
If you really want to use a certain program, such as notepad, you can do it like this:
import os
def openFile():
fileName = listbox_1.get(ACTIVE)
os.system("notepad.exe " + fileName)
Also if you need some if checks before opening the file, feel free to add them. This only shows you how to open the file.
Expanding on FatalError's suggestion with an example.
One additional benefit of using subprocessing rather than os.system is that it uses the same syntax cross-platform (os.system on Windows requires a "start" at the beginning, whereas OS X requires an "open". Not a huge deal, but one less thing to remember).
Opening a file with subprocess.call.
All you need to do to launch a program is call subprocess.call() and pass in a list of arguments where the first is the path to the program, and the rest are additional arguments that you want to supply to the program you're launching.
For instance, to launch Notepad.exe
import subprocess
path_to_notepad = 'C:\\Windows\\System32\\notepad.exe'
path_to_file = 'C:\\Users\\Desktop\\hello.txt'
subprocess.call([path_to_notepad, path_to_file])
Passing multiple arguments and paths is equally as simple. Just add additional items to the list.
Launching with multiple arguments
This, for example, launches a JAR file using a specific copy of the Java runtime environment.
import subprocess
import os
current_path = os.getcwd()
subprocess.call([current_path + '/contents/home/bin/java', # Param 1
'-jar', #Param2
current_path + '/Whoo.jar']) #param3
Argument 1 targets the program I want to launch. Argument2 supplies an argument to that program telling it that it's going to run a JAR, and finally Argument3 tells the target program where to find the file to open.
For the life of me i can't figure this one out.
I have 2 applications build in python, so 2 projects in different folders, is there a command to say in the first application like run file2 from documents/project2/test2.py ?
i tried something like os.system('') and exec() but that only seems to work if its in the same folder. How can i give a command a path like documents/project2 and then for example:
exec(documents/project2 python test2.py) ?
short version:
Is there a command that runs python test2.py while that test2 is in a completely different file/project?
thnx for all feedback!
There's a number of approaches to take.
1 - Import the .py
If the path to the other Python script can be made relative to your project, you can simply import the .py. This will cause all the code at the 'root' level of the script to be executed and makes functions as well as type and variable definitions available to the script importing it.
Of course, this only works if you control how and where everything is installed. It's the most preferable solution, but only works in limited situations.
import ..other_package.myscript
2 - Evaluate the code
You can load the contents of the Python file like any other text file and execute the contents. This is considered more of a security risk, but given the interpreted nature of Python in normal use not that much worse than an import under normal circumstances.
Here's how:
with open('/path/to/myscript.py', 'r') as f:
exec(f.read())
Note that, if you need to pass values to code inside the script, or out of it, you probably want to use files in this case.
I'd consider this the least preferable solution, due to it being a bit inflexible and not very secure, but it's definitely very easy to set up.
3 - Call it like any other external program
From a Python script, you can call any other executable, that includes Python itself with another script.
Here's how:
from subprocess import run
run('python path/to/myscript.py')
This is generally the preferable way to go about it. You can use the command line to interface with the script, and capture the output.
You can also pipe in text with stdin= or capture the output from the script with stdout=, using subprocess.Popen directly.
For example, take this script, called quote.py
import sys
text = sys.stdin.read()
print(f'In the words of the poet:\n"{text}"')
This takes any text from standard in and prints them with some extra text, to standard out like any Python script. You could call it like this:
dir | python quote.py
To use it from another Python script:
from subprocess import Popen, PIPE
s_in = b'something to say\nright here\non three lines'
p = Popen(['python', 'quote.py'], stdin=PIPE, stdout=PIPE)
s_out, _ = p.communicate(s_in)
print('Here is what the script produced:\n\n', s_out.decode())
Try this:
exec(open("FilePath").read())
It should work if you got the file path correct.
Mac example:
exec(open("/Users/saudalfaris/Desktop/Test.py").read())
Windows example:
exec(open("C:\Projects\Python\Test.py").read())
Is it possible to make a python script that will delete the .py file at the end of its execution (self-delete) in windows?
This way makes your program non OS dependant.
from os import remove
from sys import argv
remove(argv[0])
Bonus points:
When parsing arguments the very first argument that you get in sys.argv is equals to "path-to-filename/filename.py"
Neomind's answer seems to do the trick. But if deleting the file while it's in memory bothers you, and you're looking for a pure python solution, then you could use subprocess to create a new process with the explicit purpose of deleting your original script file. Something like this should work:
import sys, subprocess
subprocess.Popen("python -c \"import os, time; time.sleep(1); os.remove('{}');\"".format(sys.argv[0]))
sys.exit(0)
You probably wouldn't need the timeout in there but I've added it just to make sure that the process from the original script has been given enough time to close itself.
I'm not sure deleting a file while it's in memory would be a good idea. Try running a batch file from the script which closes the script process, then deletes the script file.
There may be a native method to self destruct a script, but I am not aware of it.
EDIT: Here is a simple example of how you could accomplish this using the method I described:
In the script
# C:\test.py
import os
os.startfile(r"C:\sampleBatch.bat")
In the batch
# C:\sampleBatch.bat
TASKKILL /IM "process name" #For me, this was "ipy64.exe" because I use IronPython.
DEL "C:\test.py"
You may not even need to kill the process to delete the file, but it is safer to do so. Hope this helps.
Yes, you could use the following:
import os
import sys
import subprocess
# execute and remove after run
(Your python code)
# end of file
dir = os.getcwd()
os.remove(dir+'\%s' % sys.argv[0])
This script can be modified of course, but besides that this should work
You could also make use of the atexit module.
import os, atexit
atexit.register(lambda file = __file__: os.remove(file))
There is a rather simple method:
import os
os.remove("insert the file's path")
If you're facing problems, place an 'r' before the starting quotations mark.
Is it possible to make a python script that will delete the .py file at the end of its execution (self-delete) in windows?
This way makes your program non OS dependant.
from os import remove
from sys import argv
remove(argv[0])
Bonus points:
When parsing arguments the very first argument that you get in sys.argv is equals to "path-to-filename/filename.py"
Neomind's answer seems to do the trick. But if deleting the file while it's in memory bothers you, and you're looking for a pure python solution, then you could use subprocess to create a new process with the explicit purpose of deleting your original script file. Something like this should work:
import sys, subprocess
subprocess.Popen("python -c \"import os, time; time.sleep(1); os.remove('{}');\"".format(sys.argv[0]))
sys.exit(0)
You probably wouldn't need the timeout in there but I've added it just to make sure that the process from the original script has been given enough time to close itself.
I'm not sure deleting a file while it's in memory would be a good idea. Try running a batch file from the script which closes the script process, then deletes the script file.
There may be a native method to self destruct a script, but I am not aware of it.
EDIT: Here is a simple example of how you could accomplish this using the method I described:
In the script
# C:\test.py
import os
os.startfile(r"C:\sampleBatch.bat")
In the batch
# C:\sampleBatch.bat
TASKKILL /IM "process name" #For me, this was "ipy64.exe" because I use IronPython.
DEL "C:\test.py"
You may not even need to kill the process to delete the file, but it is safer to do so. Hope this helps.
Yes, you could use the following:
import os
import sys
import subprocess
# execute and remove after run
(Your python code)
# end of file
dir = os.getcwd()
os.remove(dir+'\%s' % sys.argv[0])
This script can be modified of course, but besides that this should work
You could also make use of the atexit module.
import os, atexit
atexit.register(lambda file = __file__: os.remove(file))
There is a rather simple method:
import os
os.remove("insert the file's path")
If you're facing problems, place an 'r' before the starting quotations mark.
In relation to another question, how do you account for paths that may change? For example, if a program is calling a file in the same directory as the program, you can simply use the path ".\foo.py" in *nix. However, apparently Windows likes to have the path hard-coded, e.g. "C:\Python_project\foo.py".
What happens if the path changes? For example, the file may not be on the C: drive but on a thumb drive or external drive that can change the drive letter. The file may still be in the same directory as the program but it won't match the drive letter in the code.
I want the program to be cross-platform, but I expect I may have to use os.name or something to determine which path code block to use.
Simple answer: You work out the absolute path based on the environment.
What you really need is a few pointers. There are various bits of runtime and environment information that you can glean from various places in the standard library (and they certainly help me when I want to deploy an application on windows).
So, first some general things:
os.path - standard library module with lots of cross-platform path manipulation. Your best friend. "Follow the os.path" I once read in a book.
__file__ - The location of the current module.
sys.executable - The location of the running Python.
Now you can fairly much glean anything you want from these three sources. The functions from os.path will help you get around the tree:
os.path.join('path1', 'path2') - join path segments in a cross-platform way
os.path.expanduser('a_path') - find the path a_path in the user's home directory
os.path.abspath('a_path') - convert a relative path to an absolute path
os.path.dirname('a_path') - get the directory that a path is in
many many more...
So combining this, for example:
# script1.py
# Get the path to the script2.py in the same directory
import os
this_script_path = os.path.abspath(__file__)
this_dir_path = os.path.dirname(this_script_path)
script2_path = os.path.join(this_dir_path, 'script2.py')
print script2_path
And running it:
ali#work:~/tmp$ python script1.py
/home/ali/tmp/script2.py
Now for your specific case, it seems you are slightly confused between the concept of a "working directory" and the "directory that a script is in". These can be the same, but they can also be different. For example the "working directory" can be changed, and so functions that use it might be able to find what they are looking for sometimes but not others. subprocess.Popen is an example of this.
If you always pass paths absolutely, you will never get into working directory issues.
If your file is always in the same directory as your program then:
def _isInProductionMode():
""" returns True when running the exe,
False when running from a script, ie development mode.
"""
return (hasattr(sys, "frozen") or # new py2exe
hasattr(sys, "importers") # old py2exe
or imp.is_frozen("__main__")) #tools/freeze
def _getAppDir():
""" returns the directory name of the script or the directory
name of the exe
"""
if _isInProductionMode():
return os.path.dirname(sys.executable)
return os.path.dirname(__file__)
should work. Also, I've used py2exe for my own application, and haven't tested it with other exe conversion apps.
What -- specifically -- do you mean by "calling a file...foo.py"?
Import? If so, the path is totally outside of your program. Set the PYTHONPATH environment variable with . or c:\ or whatever at the shell level. You can, for example, write 2-line shell scripts to set an environment variable and run Python.
Windows
SET PYTHONPATH=C:\path\to\library
python myapp.py
Linux
export PYTHONPATH=./relative/path
python myapp.py
Execfile? Consider using import.
Read and Eval? Consider using import.
If the PYTHONPATH is too complicated, then put your module in the Python lib/site-packages directory, where it's put onto the PYTHONPATH by default for you.
I figured out by using os.getcwd(). I also learned about using os.path.join to automatically determine the correct path format based on the OS. Here's the code:
def openNewRecord(self, event): # wxGlade: CharSheet.<event_handler>
"""Create a new, blank record sheet."""
path = os.getcwd()
subprocess.Popen(os.path.join(path, "TW2K_char_rec_sheet.py"), shell=True).stdout
It appears to be working. Thanks for the ideas.