' Python ' is not an internal or external command, it is not a running program or a batch file.
After I install Python in D, enter Python to display the following questions
D:\>python
' python ' is not an internal or external command, nor a running program
or batch file.
The essence of this problem is that Windows CMD does not recognize the Python symbol (that is, the symbol is an executable program), because Windows is similar here and encounters a character that first queries the default path to see if the symbol is an executable program
The newly installed Python is installed under D-Disk python, which is not a default path to Windows, so Windows queries the symbol for Python under its own default path, so it will report the wrong solution .
Add the installation path for Python to the working path to Windows 1.win7
Right click on My Computer-> properties-> Advanced System Configuration-> Click on the Advanced column, where the field to open the environment variable-> in the system variable path to join the Python installation path, such as mine is D:\Python27
Enter python-v in cmd to check if the settings are successful 2.win10
Right key win four square symbol, select the system-> advanced system settings, in which select the Advanced column, where the bar to open the environment variable-> in the system variable path to join the Python installation path, such as mine is D:\Python27
Enter python-v in cmd to check if the settings are successful