Let's say you have some nested for-loop that you want to break out of from the inner loop:

x = default
for key, values in dict_of_sets:
for value in values:
if predicate(value):
x = key
break 2  # INVALID SYNTAX, SADLY...

Well, it turns out that Python supports for-else, so this can be made trivial:

x = default_value
for key, values in dict_of_sets:
for value in values:
if predicate(key, value):
x = value
break  # THIS BREAKS BOTH LOOPS!
else:
continue
break

You don't need to know why this works to use it; but, if you do, here's how it works:

• When the inner for-loop exhausts, its else-clause executes next, which continues the program through that iteration of the outer for-loop (quietly skipping the break statement on line 9).
• If the inner for-loop is, instead, killed with the break on line 6, its else-clause is skipped, allowing the break statement on line 9 to execute and terminate the outer for-loop.

This can be used as much as you like:

for i in range(3):
for j in range(3):
for k in range(3):
for l in range(3):
for m in range(3):
for n in range(3):
print(i, j, k, l, m, n)
if input("Press enter to continue, or type anything to break out of all these loops.\n> "):
break  # THIS WILL BREAK ALL OF THE LOOPS!
else:
continue
break
else:
continue
break
else:
continue
break
else:
continue
break
else:
continue
break

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