I’ve been trying to add the Python path to the command line on Windows 7, yet no matter the method I try, nothing seems to work. I’ve used the set command, I’ve tried adding it through the Edit Environment variables prompt etc.
Further more if I run the set command on the command line it lists this
python = c:\python27
Yet it still doesn’t recognize the Python command.
Reading the documentation, and various other sources hasn’t seemed to help.
Edit: Just to clarify further, I’ve appended the path of the Python executable to PATH in edit environment prompt. Doesn’t seem to work.
When setting Environmental Variables in Windows, I have gone wrong on many, many occasions.
I thought I should share a few of my past mistakes here hoping that it might help someone.
(These apply to all Environmental Variables, not just when setting Python Path)
Watch out for these possible mistakes:
Kill and reopen your shell window: Once you make a change to the ENVIRONMENTAL Variables, you have to restart the window you are testing it on.
NO SPACES when setting the Variables. Make sure that you are adding the ;C:\Python27 WITHOUT any spaces. (It is common to try C:\SomeOther; C:\Python27 That space (␣) after the semicolon is not okay.)
USE A BACKWARD SLASH when spelling out your full path. You will see forward slashes when you try echo $PATH but only backward slashes have worked for me.
DO NOT ADD a final backslash. Only C:\Python27 NOT C:\Python27\
You can set the path from the current cmd window using the PATH = command. That will only add it for the current cmd instance. if you want to add it permanently, you should add it to system variables. (Computer > Advanced System Settings > Environment Variables)
You would goto your cmd instance, and put in PATH=C:/Python27/;%PATH%.
# coding: utf-8import sys
import os
import time
import _winreg
import ctypes
def find_python():"""
retrieves the commandline for .py extensions from the registry
"""
hKey = _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT,
r'Python.File\shell\open\command')# get the default value
value, typ = _winreg.QueryValueEx(hKey,None)
program = value.split('"')[1]ifnot program.lower().endswith(r'\python.exe'):returnNonereturn os.path.dirname(program)def extend_path(pypath, remove=False, verbose=0, remove_old=True,
script=False):"""
extend(pypath) adds pypath to the PATH env. variable as defined in the
registry, and then notifies applications (e.g. the desktop) of this change.
!!! Already opened DOS-Command prompts are not updated. !!!
Newly opened prompts will have the new path (inherited from the
updated windows explorer desktop)
options:
remove (default unset), remove from PATH instead of extend PATH
remove_old (default set), removes any (old) python paths first
script (default unset), try to add/remove the Scripts subdirectory
of pypath (pip, easy_install) as well
"""
_sd ='Scripts'# scripts subdir
hKey = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE,
r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment',0, _winreg.KEY_READ | _winreg.KEY_SET_VALUE)
value, typ = _winreg.QueryValueEx(hKey,"PATH")
vals = value.split(';')assert isinstance(vals, list)ifnot remove and remove_old:
new_vals =[]for v in vals:
pyexe = os.path.join(v,'python.exe')if v != pypath and os.path.exists(pyexe):if verbose >0:print'removing from PATH:', v
continueif script and v != os.path.join(pypath, _sd)and \
os.path.exists(v.replace(_sd, pyexe)):if verbose >0:print'removing from PATH:', v
continue
new_vals.append(v)
vals = new_vals
if remove:try:
vals.remove(pypath)exceptValueError:if verbose >0:print'path element', pypath,'not found'returnif script:try:
vals.remove(os.path.join(pypath, _sd))exceptValueError:passprint'removing from PATH:', pypath
else:if pypath in vals:if verbose >0:print'path element', pypath,'already in PATH'return
vals.append(pypath)if verbose >1:print'adding to PATH:', pypath
if script:ifnot pypath +'\\Scripts'in vals:
vals.append(pypath +'\\Scripts')if verbose >1:print'adding to PATH:', pypath +'\\Scripts'
_winreg.SetValueEx(hKey,"PATH",0, typ,';'.join(vals))
_winreg.SetValueEx(hKey,"OLDPATH",0, typ, value )
_winreg.FlushKey(hKey)# notify other programsSendMessage= ctypes.windll.user32.SendMessageW
HWND_BROADCAST =0xFFFF
WM_SETTINGCHANGE =0x1ASendMessage(HWND_BROADCAST, WM_SETTINGCHANGE,0, u'Environment')if verbose >1:print'Do not forget to restart any command prompts'if __name__ =='__main__':
remove ='--remove'in sys.argv
script ='--noscripts'notin sys.argv
extend_path(find_python(), verbose=2, remove=remove, script=script)
The following program will add the python executable path and the subdir Scripts (which is where e.g. pip and easy_install are installed) to your environment. It finds the path to the python executable from the registry key binding the .py extension. It will remove old python paths in your environment. Works with XP (and probably Vista) as well.
It only uses modules that come with the basic windows installer.
# coding: utf-8
import sys
import os
import time
import _winreg
import ctypes
def find_python():
"""
retrieves the commandline for .py extensions from the registry
"""
hKey = _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT,
r'Python.File\shell\open\command')
# get the default value
value, typ = _winreg.QueryValueEx (hKey, None)
program = value.split('"')[1]
if not program.lower().endswith(r'\python.exe'):
return None
return os.path.dirname(program)
def extend_path(pypath, remove=False, verbose=0, remove_old=True,
script=False):
"""
extend(pypath) adds pypath to the PATH env. variable as defined in the
registry, and then notifies applications (e.g. the desktop) of this change.
!!! Already opened DOS-Command prompts are not updated. !!!
Newly opened prompts will have the new path (inherited from the
updated windows explorer desktop)
options:
remove (default unset), remove from PATH instead of extend PATH
remove_old (default set), removes any (old) python paths first
script (default unset), try to add/remove the Scripts subdirectory
of pypath (pip, easy_install) as well
"""
_sd = 'Scripts' # scripts subdir
hKey = _winreg.OpenKey (_winreg.HKEY_LOCAL_MACHINE,
r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment',
0, _winreg.KEY_READ | _winreg.KEY_SET_VALUE)
value, typ = _winreg.QueryValueEx (hKey, "PATH")
vals = value.split(';')
assert isinstance(vals, list)
if not remove and remove_old:
new_vals = []
for v in vals:
pyexe = os.path.join(v, 'python.exe')
if v != pypath and os.path.exists(pyexe):
if verbose > 0:
print 'removing from PATH:', v
continue
if script and v != os.path.join(pypath, _sd) and \
os.path.exists(v.replace(_sd, pyexe)):
if verbose > 0:
print 'removing from PATH:', v
continue
new_vals.append(v)
vals = new_vals
if remove:
try:
vals.remove(pypath)
except ValueError:
if verbose > 0:
print 'path element', pypath, 'not found'
return
if script:
try:
vals.remove(os.path.join(pypath, _sd))
except ValueError:
pass
print 'removing from PATH:', pypath
else:
if pypath in vals:
if verbose > 0:
print 'path element', pypath, 'already in PATH'
return
vals.append(pypath)
if verbose > 1:
print 'adding to PATH:', pypath
if script:
if not pypath + '\\Scripts' in vals:
vals.append(pypath + '\\Scripts')
if verbose > 1:
print 'adding to PATH:', pypath + '\\Scripts'
_winreg.SetValueEx(hKey, "PATH", 0, typ, ';'.join(vals) )
_winreg.SetValueEx(hKey, "OLDPATH", 0, typ, value )
_winreg.FlushKey(hKey)
# notify other programs
SendMessage = ctypes.windll.user32.SendMessageW
HWND_BROADCAST = 0xFFFF
WM_SETTINGCHANGE = 0x1A
SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, 0, u'Environment')
if verbose > 1:
print 'Do not forget to restart any command prompts'
if __name__ == '__main__':
remove = '--remove' in sys.argv
script = '--noscripts' not in sys.argv
extend_path(find_python(), verbose=2, remove=remove, script=script)
I know this post is old but I’d like to add that the solutions assume admin privs. If you don’t have those you can:
Go to control panel, type path (this is Windows 7 now so that’s in the Search box) and click “Edit Environment variables for your account”. You’ll now see the Environment Variable dialog with “User variables” on the top and “System variables” below.
You can, as a user, click the top “New” button and add:
Variable name: PATH
Variable value: C:\Python27
(no spaces anywhere) and click OK. Once your command prompt is restarted, any PATH in the User variables is appended to the end of the System Path. It doesn’t replace the PATH in any other way.
If you want a specific full path set up, you’re better off creating a batch file like this little one:
@echo off
PATH C:\User\Me\Programs\mingw\bin;C:\User\Me\Programs;C:\Windows\system32
title Compiler Environment - %Username%@%Computername%
cmd
Call it “compiler.bat” or whatever and double click to start it. Or link to it. Or pin it etc…
You need to make changes in your system variable
— Right click on “My computer”
— Click “Properties”
— Click “Advanced system settings” in the side panel
— Click on Environment Variable — You will two sections of user variable and system variable
— Under system variable section search for the variable ‘Path’ click on edit and add "C:\Python27;" (without quotes) save it
— Now open command line type ‘path’ hit enter you will see path variable has been modified
— Now type python --version you will see the python version
For anyone trying to achieve this with Python 3.3+, the Windows installer now includes an option to add python.exe to the system search path. Read more in the docs.
Working with Windows environment variables is always a horrible experience. Recently, I found an amazing tool called Rapid Environment Editor, which gives an awesomely simple GUI for managing them.
Re-reading this, it sounds like a paid shill, but I swear I’m not! It’s just been one of the most useful utilities in my toolkit for a while and I’m surprised no one seems to know about it.
If Python was installed with another program, such as ArcGIS 10.1 in my case, then you also must include any extra folders that path to the python.exe in your Environment Variables.
So my Environment Variables looks like this:
System variables > Path > add ;C:\Python27\ArcGIS10.1
This question is pretty old, but I just ran into a similar problem and my particular solution wasn’t listed here:
Make sure you don’t have a folder in your PATH that doesn’t exist.
In my case, I had a bunch of default folders (Windows, Powershell, Sql Server, etc) and then a custom C:\bin that I typically use, and then various other tweaks like c:\python17, etc. It turns out that the cmd processor was finding that c:\bin didn’t exist and then stopped processing the rest of the variable.
Also, I don’t know that I ever would have noticed this without PATH manager. It nicely highlighted the fact that that item was invalid.
I just installed Python 3.3 on Windows 7 using the option “add python to PATH”.
In PATH variable, the installer automatically added a final backslash: C:\Python33\
and so it did not work on command prompt (i tried closing/opening the prompt several times)
I removed the final backslash and then it worked: C:\Python33
If you have got frustrated by setting the path for the python just download the new version of python uninstall the older version of the python and while installing the new version it will ask whether to set path mark that and install