Asun Friere a écrit :
On Nov 27, 6:11 am, Nan <[EMAIL PROTECTED]> wrote:
Hello,
I just started to use Python. I wrote the following code and
expected 'main' would be called.
def main():
print "hello"
main
Not an answer to your question, but I dislike functions named 'main'
because the situation they occur in would better be dealt with by
exploiting the name of the built-in module '__main__'. But maybe
that's just me.
However, consider your code rewritten thusly:
def greet () :
print "hello"
if __name__ == '__main__' :
greet()
(A more literal translation of your program would be:
if __name__ == '__main__' : print 'hello')
This little trick ensures that greet() will execute if the module is
itself executed as a script, but that it won't if you import it from
elsewhere (ie. another script or the intepreter).
IMHO, it's good practice, wherever you may be tempted to write 'def
main()', intending this to be the glue code for your various functions
etc, instead to test whether the code is running as __main__ as above.
The problem is that you often have more to do in the __main__ section of
a script than just calling one simple function, and you don't
necessarily want to pollute the module's namespace with all this code.
What I usually do is to have a main function called from the __main__
section, ie:
# myscript.py
# imports here
# classes and functions def here
def main(argv):
# parse args
# do whathever
return exit_status
if __name__ == "__main__":
import sys
sys.exit(main(sys.argv))
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