Hidden features of Python [closed]

Answer 1

The for...else syntax (see http://docs.python.org/ref/for.html )

for i in foo:
    if i == 0:
        break
else:
    print("i was never 0")

The "else" block will be normally executed at the end of the for loop, unless the break is called.

The above code could be emulated as follows:

found = False
for i in foo:
    if i == 0:
        found = True
        break
if not found: 
    print("i was never 0")