setting PATH in windows using python

Question

Hi I am trying to check for java version by using below python code

os.environ["PATH"] = os.environ["PATH"] + os.pathsep + "C:\Program Files\Java\jdk1.8.0_20\bin"
os.system("java -version")

but it shows this error message

'java' is not recognized as an internal or external command, operable program or batch file.

Answer 1

'\\b' is a BACKSPACE character, not \\ and b .

>>> "\b"
'\x08'
>>> print("\b")

To represent \\ and b literally, you need to escape \\ , or use r'raw string literal' :

>>> print("\\b")
\b
>>> print(r"\b")
\b

Answer 2

I tried to print the PATH

os.system("echo %PATH%")

then I found some weird text like below

C:\Program Files\Java\jdk1.8.0_20in

\\b in \\bin is showing as backspace char in path

replace path with below works fine

C:\\Program Files\\Java\\jdk1.8.0_20\\bin