Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.9k views
in Technique[技术] by (71.8m points)

python: sys is not defined

I have a piece of code which is working in Linux, and I am now trying to run it in windows, I import sys but when I use sys.exit(). I get an error, sys is not defined. Here is the begining part of my code

try:
    import numpy as np
    import pyfits as pf
    import scipy.ndimage as nd
    import pylab as pl
    import os
    import heapq
    import sys
    from scipy.optimize import leastsq

except ImportError:
    print "Error: missing one of the libraries (numpy, pyfits, scipy, matplotlib)"
    sys.exit()

Why is sys not working??

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Move import sys outside of the try-except block:

import sys
try:
    # ...
except ImportError:
    # ...

If any of the imports before the import sys line fails, the rest of the block is not executed, and sys is never imported. Instead, execution jumps to the exception handling block, where you then try to access a non-existing name.

sys is a built-in module anyway, it is always present as it holds the data structures to track imports; if importing sys fails, you have bigger problems on your hand (as that would indicate that all module importing is broken).


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...