Returns a set containing the length of each string in the given iterable, removing duplicates.

Expresses a concise set comprehension that maps each string to its length and collects unique lengths.

When you need to know the distinct lengths of strings in a collection, e.g., for validating input sizes or analyzing text.

Text processing, data validation, algorithmic challenges involving string lengths.

{len(item) for item in iterable}

{len(item) for item in iterable}

item: variable representing each element (typically a string), iterable: any iterable of strings (e.g., list, tuple, set)

• len
• str
• list
• set
• comprehension
• for

• Replace len with any function returning an integer (e.g.
• len
• sum
• custom)
• replace the iterable with any collection of strings
• add a filter: {len(s) for s in iterable if condition}

Expecting a list with duplicates; applying len to non‑sized objects; confusing set with dict comprehension; forgetting the result is unordered.

List comprehension preserves duplicates and order; dict comprehension maps each string to its length; map(len, iterable) yields an iterator of lengths.

Do not confuse set syntax with dict syntax; remember sets discard duplicates and have no ordering; ensure elements are sized before applying len.

• set comprehension patterns

The result is an unordered set; duplicate lengths are collapsed, so the output may be smaller than the input.

Conveys a functional, declarative intent to compute unique lengths, emphasizing brevity and immutability.

Think ‘lengths of strings as a set’.

Useful for quick checks of distinct string lengths; for frequency counts prefer collections.Counter.

Consider using collections.Counter if you need the frequency of each length, or a list if you need ordered duplicates.