s.replace(ss [from] [nc])
s - str variable.
ss - replacement string. Can be string or numeric expression.
from - where to do the replacement. 0-based character index in s. Default: 0.
nc - number of characters to replace. Default: -1 (all characters at right from from).
Replaces range of characters in s.
str s = "one two three" s.replace("four" 4 3) now s is "one four three"