INSERT

INSERT(str1, pos, len, str2)

Inserts str2 into str1 at position pos (1-indexed), replacing the first len characters after pos in the process. If len is zero, inserts str2 into str1 without deleting any characters. If pos is one, prepends str2 to str1. If pos is larger than the length of str1, appends str2 to str1.

Note

Behavior when pos or len are negative is not well-defined at this time.