REGEX: Matching a String to a Regular Expression

How to:

The REGEX function matches a string to a regular expression and returns true (1) if it matches and false (0) if it does not match.

A regular expression is a sequence of special characters and literal characters that you can combine to form a search pattern.

Many references for regular expressions exist on the web.

For a basic summary, see the section Summary of Regular Expressions in Chapter 2, Security, of the Server Administration manual.

Syntax: How to Match a String to a Regular Expression 

REGEX(string, regular_expression)

where:

string

Alphanumeric

Is the character string to match.

regular_expression

Alphanumeric

Is a regular expression enclosed in single quotation marks constructed using literals and metacharacters. The following metacharacters are supported

  • . represents any single character
  • * represents zero or more occurrences
  • + represents one or more occurrences
  • ? represents zero or one occurrence
  • ^ represents beginning of line
  • $ represents end of line
  • [] represents any one character in the set listed within the brackets
  • [^] represents any one character not in the set listed within the brackets
  • | represents the Or operator
  • \ is the Escape Special Character
  • () contains a character sequence

For example, the regular expression '^Ste(v|ph)en$' matches values starting with Ste followed by either ph or v, and ending with en.

Note: The output value is numeric.

Example: Matching a String Against a Regular Expression

The following request matches the FIRSTNAME field against the regular expression '^Sara(h?)$', which matches Sara or Sarah: 

TABLE FILE WF_RETAIL_LITE
PRINT FIRSTNAME AND COMPUTE
REG1/I1=REGEX(FIRSTNAME,'^Sara(h?)$') ;
BY LASTNAME/A10
WHERE LASTNAME EQ 'Allen'
END

The output is 

              First           
  LASTNAME    Name                  REG1    
  --------    -----                 ----           
  Allen       Penny                    0
              Rosemary                 0
              Amber                    0
              Julie                    0
              Sarah                    1
              Leo                      0
              Margret                  0
              Donna                    0
              Damian                   0
              Alexander                0
              Diego                    0
              Amber                    0
              Susan                    0
              Amber                    0
              Sara                     1
              Sara                     1