MID$()
This page was last modified 15:59, 27 January 2018 by Mars2000you. Based on work by NYYRIKKI and Gdx and others.

Contents

Effect

MID$ is kind of special as it can be used both as function or as instruction:
- As function it returns a substring of variable length (y) starting at a variable position (x) in an input string A$
- As instruction it can be used to replace substring by another string.

Remark: For strings with Japanese or Korean characters, you need to use CALL KMID.

Syntaxes

Function Syntax

MID$(A$,x[,y])

Instruction Syntax

MID$(A$,x[,y])=<string>

Range

MID$ accepts an offset (x) between 1 and 255 and an optional length (y) between 0 and 255.

If no length (y) is specified then
In case of function the entire substring starting at position x is returned
In case of instruction the entire replacement string is used at position x

When (x) = 1, MID$ function replaces the LEFT$ function
MID$(A$,1,3) is equivalent to LEFT$(A$,3)

When (x) = LEN(A$)-(y)+1, MID$ function replaces the RIGHT$ function
If LEN(A$)=5 then MID$(A$,4,2) is equivalent to RIGHT$(A$,2)

Examples

MID$ as function

10 A$="www.msx.org"
20 PRINT MID$(A$,5,3)
30 PRINT MID$(A$,5)
 
RUN
msx
msx.org

MID$ as instruction

10 A$="ABCDEFG"
20 PRINT A$
30 MID$(A$,4)="XYZ"
40 PRINT A$
 
RUN
ABCDEFG
ABCXYZG

Related to

CALL KMID, LEN, LEFT$, RIGHT$

Compatibility

MSX-BASIC 1.0 or higher