Apple II User Manual

Page of 257
    ROCKW
    ROCKWE
    ROCKWEL
    ROCKWELL
    ROCKWELL R
    ROCKWELL R6
    ROCKWELL R65
    ROCKWELL R650
    ROCKWELL R6500
Since A$ has 14 characters this loop will be executed with N=1,2,3,...,13,14.  The first time
through only the first character will be printed, the second time the first two characters will be
printed, etc.
RIGHT$ FUNCTION
Another string function, called "RIGHT$," returns the right N characters from a string expression.
Try substituting "RIGHT$" for "LEFT$" in the previous example and see what happens.
MID$ FUNCTION
There is also a string function which allows us to take characters from the middle of a string.  Try
the following:
    FOR N=1 TO LEN(A$):PRINT MID$(A$,N):NEXT N
    ROCKWELL R6500
    OCKWELL R6500
    CKWELL R6500
    KWELL R6500
    WELL R6500
    ELL R6500
    LL R6500
    L R6500
     R6500
    R6500
    6500
    500
    00
    0
"MID$" returns a string starting at the Nth position of A$ so the end (last character) of A$.  The
first position of the string is position 1 and the last possible position of a string is position 255.
Very often it is desirable to extract only the Nth character from a string.  This can be done by
calling MID$ with three arguments.  The third argument specifies the number of characters to
return.
For example:
    FOR N=1 TO LEN(A$):PRINT MID$(A$,N,1),MID$(A$,N,2):NEXT N
    R         RO
    O         OC
    C         CK
    K         KW
    W         WE
    E         EL
    L         LL
    L         L
               R
    R         R6
    6         65
    5         50
    0         00
    0         0
CONCATENATION-JOINING STRINGS
Strings may also be concatenated (put or joined together) through the use of the "+" operator.
Try the following: