# .substr(start,length)

Extracts substrings form the string, starting at character number start (zero-based) and including up to length characters. A negative start value (1-based) may be used to cite a start counted from the end of the string.

> `"Hello, world".substr(0,5):` Hello

If the second argument is absent, the result runs from start through the end of the string.

> `"Hello, world".substr(7):` world

If start is negative, the substring begins -start characters from the end of the string.

> `"Hello, world".substr(-5):` world