1. Breaking out of nested loops

for x in xrange(10):
 for y in xrange(10):
     print x*y
     if x*y > 50:
         break
 else:
     continue  # only executed if the inner loop did NOT break
 break  # only executed if the inner loop DID break

The same works for deeper loops:

for x in xrange(10):
    for y in xrange(10):
        for z in xrange(10):
            print x,y,z
            if x*y*z == 30:
                break
        else:
            continue
        break
    else:
        continue
    break

reference:

https://stackoverflow.com/questions/653509/breaking-out-of-nested-loops/654002#654002