Question

I came across a strange behavior in python. I could not find information about this in the python help or on SE so here it is:

def divide(x, y):
    print 'entering divide'
    try:
        return x/y
    except:
        print 'error'
    else:
        print 'no error'
    finally:
        print 'exit'

print divide(1, 1)
print divide(1, 0)

the output:

entering divide
exit
1
entering divide
error
exit
None

It seems that python will not go inside the else block if a value is returned in the try. However, it will always go in the finally block. I don’t really understand why. Can someone help me with this logic?

thanks

Answer 1

http://docs.python.org/reference/compound_stmts.html#the-try-statement

The optional else clause is executed if and when control flows off the
end of the try clause.

Currently, control “flows off the end” except in the case of an
exception or the execution of a return, continue, or break statement.