What operation does 'for city in cities:' perform in Python?

The operation 'for city in cities:' is used in Python to iterate over items within a list, or more generally, any iterable. When this statement is executed, it takes each element from the collection named "cities" one at a time and assigns it to the variable "city." This enables the programmer to execute a block of code for each element in the iterable, allowing for operations such as printing each city, modifying the elements, or performing computations based on the cities listed.

This construct is fundamental in Python programming, enabling you to effectively manage and manipulate collections of data. The flexibility of this loop extends beyond lists to include tuples, dictionaries, and even sets, making it a versatile tool for any iterative operation you may need to perform on a sequence of items.