charmatch                package:base                R Documentation

Partial String Matching

Description:

     'charmatch' seeks matches for the elements of its first argument
     among those of its second.

Usage:

     charmatch(x, table, nomatch = NA)

Arguments:

       x: the values to be matched: converte to a character vector by
          'as.character'.

   table: the values to be matched against: converted to a character
          vector.

 nomatch: the value to be returned at non-matching positions.

Details:

     Exact matches are preferred to partial matches (those where the
     value to be matched has an exact match to the initial part of the
     target, but the target is longer).

     If there is a single exact match or no exact match and a unique
     partial match then the index of the matching value is returned; if
     multiple exact or multiple partial matches are found then '0' is
     returned and if no match is found then 'nomatch' is returned.

     'NA' values are treated as the string constant '"NA"'.

Author(s):

     This function is based on a C function written by Terry Therneau.

See Also:

     'pmatch', 'match'.

     'grep' or 'regexpr' for more general (regexp) matching of strings.

Examples:

     charmatch("", "")                             # returns 1
     charmatch("m",   c("mean", "median", "mode")) # returns 0
     charmatch("med", c("mean", "median", "mode")) # returns 2

