MID$ (statement) - mkilgore/QB64pe GitHub Wiki

The MID$ statement substitutes one or more new characters for existing characters of a previously defined STRING.

MID$(baseString$, startPosition%[,]) = replacementString$

• The baseString$ variable must exist and be large enough to contain the replacementString$.
• startPosition% specifies the string character position to start the overwrite.
• bytes% or number of characters is optional. Excess byte lenghts are ignored.
• The replacementString$ should be as long as the byte length reserved.
• The length of the original string is not changed in any case. If replacementString$ is longer, it gets clipped.

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...LOOP
   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.

• MID$ (function)
• LEFT$, RIGHT$
• INSTR, ASCII, STR$, HEX$, Bitmaps (example)
• MKI$, MKL$, MKS$, MKD$