This question already has answers here:
How do I execute a program from Python? os.system fails due to spaces in path
(10 answers)
Closed 5 years ago.
Now Consider the following idea
I'm declaring a if/elif type to run the program
Such as :
number=int(input("Enter a number :"))
If number ==0
Run program.py
Elif number ==1
Run Program2.py
Else number ==2
Run Program3.py
Now clearly the command run program.py doesn't work so what should I do to make it execute program.py incase it is selected and close the main program where we are choosing the number?
There are several ways to run external code. There is subprocess and os.system() to run any other program on the disc, then there is exec to run a code you have as a string or code object, then there is eval that is kinda similar to exec but accepts only a string and allows to supply globals and locals. Those are all builtins.
But you probably don't really want to run external scripts as scripts. It creates all sorts of problems with correctly passing sys.argv to them, and making sure they get correct stdin/stdout and everything. Nine times out of ten you're better off creating a series of functions (perhaps in other files), importing them and calling those.
You should consider to learn about subprocesses: https://docs.python.org/3/library/subprocess.html
Popen option is one of the most useful ones for stuff like that.
number=int(input("Enter a number :"))
If number == 0:
subprocess.Popen([sys.argv[0], param])
Elif number ==1:
subprocess.Popen([program2.py, param])
Else number ==2:
subprocess.Popen([program3.py, param])
Note: Number 0 would open the same file you are using to call the new processes, just in case you ever need to "clone" your own program.
Edit: Linux and windows will require you to do this differently, as:
if platform.system() == "Linux":
subprocess.Popen([sys.argv[0], param])
else:
subprocess.Popen(["python", sys.argv[0], param])
This question already has answers here:
How to clear the interpreter console?
(31 answers)
Closed 7 years ago.
Python 3.5.0
I'm working with 150-200 lines of code so it isn't the worst. But this game involves a lot of repetitive lines of code, so I was wondering if there was a command that clears the whole console (for instance if I was to write code that prints "hello world" then it clears itself and prints "hello usa" where "hello world" used to be) before outputting the next line of code. I'm hoping to do this in the code editor in IDLE instead of the shell.
I guess I didn't make it clear enough D: sorry, my bad. I tried the import os way, and it just opened up a cmd console every once and a while for about a fraction of a second. I want a command that I can write in the python code editor that comes with idle, so that whenever I run the program and the program pops up, the text will pop up on the running program, disappear, then print the next text (or next step of the program).
You could try this, You will have to import os of course, and i am hoping you are using windows
>>> import os
>>> clear = lambda: os.system('cls')
>>> clear()
in linux you can try
os.system('clear')
On *nix you could say,
os.system("clear")
Assuming windows, try:
import os
os.system('cls')
This question already has answers here:
How can I stop python.exe from closing immediately after I get an output? [duplicate]
(7 answers)
Closed 9 years ago.
A real noob question.
I just wrote my first Hello World ! python program
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
def main():
print ('Hello World !')
return 0
if __name__ == '__main__':
main()
Unfortunately, when I launch it, it opens the terminal for a fraction of a second. How to avoid that it exits straight.
I look for something like pause in Windows command line.
Wait for a keystroke:
raw_input("Press <Enter> to exit.")
This will prompt the user for input and wait until it is received, at which point, the program will exit
There's several solutions:
Launch a command line and then run your Python program in it, with python <your_file>, it'll not exit the console ;
With a good IDE, you can put a breakpoint at the end of your main (example with Pydev) ;
Ask a fake user input, which will freeze the program, waiting for the input
if __name__ == '__main__':
main()
input("Press <Enter> to exit.") # Python 3, raw_input if Py2
I have just started with Python. When I execute a python script file on Windows, the output window appears but instantaneously goes away. I need it to stay there so I can analyze my output. How can I keep it open?
You have a few options:
Run the program from an already-open terminal. Open a command prompt and type:
python myscript.py
For that to work you need the python executable in your path. Just check on how to edit environment variables on Windows, and add C:\PYTHON26 (or whatever directory you installed python to).
When the program ends, it'll drop you back to the cmd prompt instead of closing the window.
Add code to wait at the end of your script. For Python2, adding ...
raw_input()
... at the end of the script makes it wait for the Enter key. That method is annoying because you have to modify the script, and have to remember removing it when you're done. Specially annoying when testing other people's scripts. For Python3, use input().
Use an editor that pauses for you. Some editors prepared for python will automatically pause for you after execution. Other editors allow you to configure the command line it uses to run your program. I find it particularly useful to configure it as "python -i myscript.py" when running. That drops you to a python shell after the end of the program, with the program environment loaded, so you may further play with the variables and call functions and methods.
cmd /k is the typical way to open any console application (not only Python) with a console window that will remain after the application closes. The easiest way I can think to do that, is to press Win+R, type cmd /k and then drag&drop the script you want to the Run dialog.
Start the script from an already open cmd window or
at the end of the script add something like this, in Python 2:
raw_input("Press enter to exit;")
Or, in Python 3:
input("Press enter to exit;")
To keep your window open in case of exception (yet, while printing the exception)
Python 2
if __name__ == '__main__':
try:
## your code, typically one function call
except Exception:
import sys
print sys.exc_info()[0]
import traceback
print traceback.format_exc()
print "Press Enter to continue ..."
raw_input()
To keep the window open in any case:
if __name__ == '__main__':
try:
## your code, typically one function call
except Exception:
import sys
print sys.exc_info()[0]
import traceback
print traceback.format_exc()
finally:
print "Press Enter to continue ..."
raw_input()
Python 3
For Python3 you'll have to use input() in place of raw_input(), and of course adapt the print statements.
if __name__ == '__main__':
try:
## your code, typically one function call
except BaseException:
import sys
print(sys.exc_info()[0])
import traceback
print(traceback.format_exc())
print("Press Enter to continue ...")
input()
To keep the window open in any case:
if __name__ == '__main__':
try:
## your code, typically one function call
except BaseException:
import sys
print(sys.exc_info()[0])
import traceback
print(traceback.format_exc())
finally:
print("Press Enter to continue ...")
input()
you can combine the answers before: (for Notepad++ User)
press F5 to run current script and type in command:
cmd /k python -i "$(FULL_CURRENT_PATH)"
in this way you stay in interactive mode after executing your Notepad++ python script and you are able to play around with your variables and so on :)
Create a Windows batch file with these 2 lines:
python your-program.py
pause
Using atexit, you can pause the program right when it exits. If an error/exception is the reason for the exit, it will pause after printing the stacktrace.
import atexit
# Python 2 should use `raw_input` instead of `input`
atexit.register(input, 'Press Enter to continue...')
In my program, I put the call to atexit.register in the except clause, so that it will only pause if something went wrong.
if __name__ == "__main__":
try:
something_that_may_fail()
except:
# Register the pause.
import atexit
atexit.register(input, 'Press Enter to continue...')
raise # Reraise the exception.
In python 2 you can do it with: raw_input()
>>print("Hello World!")
>>raw_input('Waiting a key...')
In python 3 you can do it with: input()
>>print("Hello world!")
>>input('Waiting a key...')
Also, you can do it with the time.sleep(time)
>>import time
>>print("The program will close in 5 seconds")
>>time.sleep(5)
On Python 3
input('Press Enter to Exit...')
Will do the trick.
You can just write
input()
at the end of your code
therefore when you run you script it will wait for you to enter something
{ENTER for example}
I had a similar problem. With Notepad++ I used to use the command : C:\Python27\python.exe "$(FULL_CURRENT_PATH)" which closed the cmd window immediately after the code terminated.
Now I am using cmd /k c:\Python27\python.exe "$(FULL_CURRENT_PATH)" which keeps the cmd window open.
To just keep the window open I agree with Anurag and this is what I did to keep my windows open for short little calculation type programs.
This would just show a cursor with no text:
raw_input()
This next example would give you a clear message that the program is done and not waiting on another input prompt within the program:
print('You have reached the end and the "raw_input()" function is keeping the window open')
raw_input()
Note!
(1) In python 3, there is no raw_input(), just
input().
(2) Use single quotes to indicate a string; otherwise if you type doubles around anything, such as
"raw_input()", it will think it is a function, variable, etc, and not text.
In this next example, I use double quotes and it won't work because it thinks there is a break in the quotes between "the" and "function" even though when you read it, your own mind can make perfect sense of it:
print("You have reached the end and the "input()" function is keeping the window open")
input()
Hopefully this helps others who might be starting out and still haven't figured out how the computer thinks yet. It can take a while. :o)
If you want to run your script from a desktop shortcut, right click your python file and select Send to|Desktop (create shortcut). Then right click the shortcut and select Properties. On the Shortcut tab select the Target: text box and add cmd /k in front of the path and click OK. The shortcut should now run your script without closing and you don't need the input('Hit enter to close')
Note, if you have more than one version of python on your machine, add the name of the required python executable between cmd /k and the scipt path like this:
cmd /k python3 "C:\Users\<yourname>\Documents\your_scipt.py"
Apart from input and raw_input, you could also use an infinite while loop, like this:
while True: pass (Python 2.5+/3) or while 1: pass (all versions of Python 2/3). This might use computing power, though.
You could also run the program from the command line. Type python into the command line (Mac OS X Terminal) and it should say Python 3.?.? (Your Python version) It it does not show your Python version, or says python: command not found, look into changing PATH values (enviromentl values, listed above)/type C:\(Python folder\python.exe. If that is successful, type python or C:\(Python installation)\python.exe and the full directory of your program.
A very belated answer, but I created a Windows Batch file called pythonbat.bat containing the following:
python.exe %1
#echo off
echo.
pause
and then specified pythonbat.bat as the default handler for .py files.
Now, when I double-click a .py file in File Explorer, it opens a new console window, runs the Python script and then pauses (remains open), until I press any key...
No changes required to any Python scripts.
I can still open a console window and specify python myscript.py if I want to...
(I just noticed #maurizio already posted this exact answer)
If you want to stay cmd-window open AND be in running-file directory this works at Windows 10:
cmd /k cd /d $(CURRENT_DIRECTORY) && python $(FULL_CURRENT_PATH)
I found the solution on my py3 enviroment at win10 is just run cmd or powershell as Administrator,and the output would stay at the same console window,any other type of user run python command would cause python to open a new console window.
The simplest way:
your_code()
while True:
pass
When you open the window it doesn't close until you close the prompt.
`import sys,traceback
sys.exc_info()[0]
traceback.format_exc()
print("Press Enter to exit ...")
input()`
simply write the above code after your actual code. for eg. am taking input from user and print on console hence my code will be look like this -->
`import sys,traceback
nam=input("enter your name:")
print("your name is:-{}".format(nam)) #here all my actual working is done
sys.exc_info()[0]
traceback.format_exc()
print("Press Enter to exit ...")
input()`
Try this,
import sys
stat='idlelib' in sys.modules
if stat==False:
input()
This will only stop console window, not the IDLE.
You can launch python with the -i option or set the environment variable PYTHONINSPECT=x. From the docs:
inspect interactively after running script; forces a prompt even
if stdin does not appear to be a terminal; also PYTHONINSPECT=x
So when your script crashes or finishes, you'll get a python prompt and your window will not close.
Create a function like dontClose() or something with a while loop:
import time
def dontClose():
n = 1
while n > 0:
n += 1
time.sleep(n)
then run the function after your code. for e.g.:
print("Hello, World!")
dontClose()
Go here and download and install Notepad++
Go here and download and install Python 2.7 not 3.
Start, Run Powershell. Enter the following. [Environment]::SetEnvironmentVariable("Path", "$env:Path;C:\Python27", "User")
Close Powershell and reopen it.
Make a directory for your programs. mkdir scripts
Open that directory cd scripts
In Notepad++, in a new file type: print "hello world"
Save the file as hello.py
Go back to powershell and make sure you are in the right directory by typing dir. You should see your file hello.py there.
At the Powershell prompt type: python hello.py
On windows 10 insert at beggining this:
#!/usr/bin/env python
# -*- coding: utf-8 -*-
Strange, but it work for me!(Together with input() at the end, of course)
You can open PowerShell and type "python".
After Python has been imported, you can copy paste the source code from your favourite text-editor to run the code.
The window won't close.
A simple hack to keep the window open:
counter = 0
While (True):
If (counter == 0):
# Code goes here
counter += 1
The counter is so the code won’t repeat itself.
The simplest way:
import time
#Your code here
time.sleep(60)
#end of code (and console shut down)
this will leave the code up for 1 minute then close it.