Truncate with an ellipsis in Python
Python interview exercise on Strings, difficulty 1 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write truncate(s, max_len) that returns s unchanged if it has at most max_len characters, otherwise the first max_len characters followed by "…". A Python str is a sequence of characters, not bytes, so slicing is safe with accents.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.