replaceAt

>>-replaceAt(new-,-n-,-+----------+-+-------+-)-----><
                       +-,-length-+ +-,-pad-+

Returns the receiving buffer with the characters from the [n] th character for [length] characters replaced with [new] . The replacement position and length can extend beyond the end of the receiving string. The starting position, [n] , is required and must be a positive whole number. The [length] is optional and must be a positive whole number or zero. If [length] is omitted, it defaults to the length of [new] .

If [n] is greater than the length of the receiving string, padding is added before the [new] string. The default [pad] character is a blank.