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.


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

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

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")

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).

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.

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.

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.

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.

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.