Skip to content

yield-in-for-loop (UP028)#

Derived from the pyupgrade linter.

Fix is always available.

What it does#

Checks for for loops that can be replaced with yield from expressions.

Why is this bad?#

If a for loop only contains a yield statement, it can be replaced with a yield from expression, which is more concise and idiomatic.


for x in foo:
    yield x

Use instead:

yield from foo

Fix safety#

This rule's fix is marked as unsafe, as converting a for loop to a yield from expression can change the behavior of the program in rare cases. For example, if a generator is being sent values via send, then rewriting to a yield from could lead to an attribute error if the underlying generator does not implement the send method.

In most cases, however, the fix is safe, and such a modification should have no effect on the behavior of the program.