From QB64 Wiki
The MID$ statement substitutes one or more new characters for existing characters of a previously defined STRING.
- MID$(basestring$, start_position%[, bytes%]) = string_to_add$
- The basestring variable STRING value must exist and be large enough to contain the string_to_add.
- Start position specifies the string character position to start the overwrite. Cannot be 0 or an Illegal function call error will occur!
- The byte length or number of characters is optional. Excess statement string characters or byte lenghts are ignored.
- The string value to be placed in the string should be as long as the byte length reserved.
- The length of the original string is NOT changed in any case! Excess characters will not be in the string value returned.
Example: Using INSTR to locate the string positions and a MID$ statement to change the words.
text$ = "The cats and dogs were playing, even though dogs don't like cats." PRINT text$ start% = 1 ' start cannot be 0 when used in the INSTR function! DO position% = INSTR(start%, text$, "dog") IF position% THEN ' when position is a value greater than 0 MID$(text$, position%, 3) = "rat" ' changes "dog" to "rat" when found start% = position% + 1 ' advance one position to search rest of string END IF LOOP UNTIL position% = 0 ' no other matches found PRINT text$
The cats and dogs were playing, even though dogs don't like cats. The cats and rats were playing, even though rats don't like cats.