R-INDEX function

Returns an INTEGER value that indicates the position of the target string within the source string. In contrast to the INDEX function, R-INDEX performs the search from right to left.

Syntax 

 

R-INDEX ( source , target [ , starting ] )

source

A constant, field name, variable name, or expression that results in a CHARACTER or LONGCHAR value.

target

A CHARACTER or LONGCHAR expression whose position you want to locate in source. If target does not exist within source, R-INDEX returns 0.

If a starting parameter is not specified, then the search for the target pattern begins at the right-most character. Even though the search is started from the right, the target position is calculated from the left. For example, this code returns a 3 rather than a 2:

 

R-INDEX("abcd" , "c")

starting

An integer that specifies the begin point for the search. The search is right-to-left and starts from the starting point. For example, this statement returns 1 R-INDEX("abcdefabcdef","abc",6).

Examples 

This procedure prompts you to enter a character string and a pattern to match against the string. It then displays the starting position of the string where the pattern was found.

 

r-rindex.p

DEFINE VARIABLE rindx  AS INTEGER   NO-UNDO. DEFINE VARIABLE source AS CHARACTER NO-UNDO FORMAT "X(45)". DEFINE VARIABLE target AS CHARACTER NO-UNDO FORMAT "X(45)".   REPEAT: PROMPT-FOR source LABEL "Enter a character string to do pattern matching:"     WITH FRAME s1 CENTERED. PROMPT-FOR target LABEL "Enter a pattern to match in the string:"     WITH FRAME t1 CENTERED. rindx = R-INDEX(INPUT source, INPUT target). IF rindx < > 0 THEN DO: DISPLAY "The target pattern:" INPUT target NO-LABEL       "last appears in position" rindx NO-LABEL SKIP       WITH FRAME r1 ROW 12 CENTERED. DISPLAY "in the source string:" INPUT source NO-LABEL       WITH FRAME r1 ROW 12 CENTERED. HIDE FRAME r1. END. IF rindx = 0 THEN DO: DISPLAY "The target pattern:" INPUT target NO-LABEL "could not be found" SKIP WITH FRAME r2 ROW 12 CENTERED. DISPLAY "in the source string:" INPUT source NO-LABEL WITH FRAME r2 ROW 12 CENTERED. HIDE FRAME r2. END. END.

This example also uses a starting value:

 

r-rndex.p

DEFINE VARIABLE mark       AS INTEGER   NO-UNDO. DEFINE VARIABLE line-width AS INTEGER   NO-UNDO. DEFINE VARIABLE paragraph  AS CHARACTER NO-UNDO.   paragraph = "The course centers around an existing small " + "application that you modify to improve perfo" + "rmance. Our highly-qualified instructors dem" + "onstrate proven analysis and coding techniqu" + "es and provide tips for making the most of y" + "our ABL code. You are encouraged to bri" + "ng your own application problems to class an" + "d actively participate in class discussions " + "and hands-on lab exercises.".   SET line-width LABEL "Justify with how many characters wide?"   VALIDATE(line-width >= 20 AND line-width <= 70,     "Must be between 20 and 70 for this example.")   WITH SIDE-LABELS FRAME ask.   FORM paragraph FORMAT "x(72)"   WITH DOWN NO-LABELS USE-TEXT.   DISPLAY "L" + FILL("-", line-width - 2) + "R" @ paragraph. DOWN.   DO WHILE LENGTH(paragraph) > line-width:   mark = R-INDEX(paragraph, " ", line-width).   DISPLAY SUBSTRING(paragraph, 1, mark) @ paragraph.   DOWN.   paragraph = SUBSTRING(paragraph, mark + 1). END.   IF paragraph <> "" THEN   DISPLAY paragraph.

Notes 

If either operand is case sensitive, then the R-INDEX function is also case sensitive.

If either the source string or target pattern is null, the result is 0.

The R-INDEX function is double-byte enabled. You can specify target and source strings for the R-INDEX function that contain double-byte characters.

See also 

INDEX function, LOOKUP function