Python 3 reference · Set Methods

Python Set pop() Method

Remove and return an arbitrary element of the set. Raises KeyError if the set is empty.

Syntax

set.pop()

The removed element.

Take an elementTry it yourself

s = {"only"}
print(s.pop(), s)

Output

only set()

Process every element (order not guaranteed)Try it yourself

pending = {3, 1, 2}
done = []
while pending:
    done.append(pending.pop())
print(sorted(done))

Output

[1, 2, 3]

Sets are unordered, so you can't choose which element pop() returns.

Version	Change
Python 3.0	Added

set.discard() · Remove an element if it is present; do nothing if it isn't. The no-error version of remove().
set.remove() · Remove an element from the set. Raises KeyError if it isn't present; use discard() to avoid the error.
set.clear() · Remove every element from the set in place, leaving an empty set. Other references to the set see the change.
Python Sets · tutorial