Python Leave Loop Early

Question

How do I leave a loop early in python?

for a in b:     if criteria in list1:         print "oh no"         #Force loop i.e. force next iteration without going on     someList.append(a) 

Also, in java you can break out of a loop, is there an equivalent in Python?

Answer 1

continue and break is what you want. Python works identically to Java/C++ in this regard.

Answer 2

Firstly, bear in mind it might be possible to do what you want with a list comprehension. So you might be able to use something like:

somelist = [a for a in b if not a.criteria in otherlist] 

If you want to leave a loop early in Python you can use break, just like in Java.

>>> for x in xrange(1,6): ...     print x ...     if x == 2: ...         break ... 1 2 

If you want to start the next iteration of the loop early you use continue, again just as you would in Java.

>>> for x in xrange(1,6): ...     if x == 2: ...         continue ...     print x ... 1 3 4 5 

Here's the documentation for break and continue. This also covers else clauses for loops, which aren't run when you break.