# `len`

The `len` built-in function is a useful concept to solve the [hamming][hamming] and [variable-length-quantity][variable-length-quantity.md] exercises.

TODO: ADD MORE DETAIL

See [docs][docs].

[docs]: https://docs.python.org/3/library/functions.html#len
[hamming]: ../../exercise-concepts/hamming.md
[variable-length-quantity]: ../../exercise-concepts/variable-length-quantity.md
