| % File src/library/base/man/charmatch.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2016 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{charmatch} |
| \title{Partial String Matching} |
| \usage{ |
| charmatch(x, table, nomatch = NA_integer_) |
| } |
| \alias{charmatch} |
| \arguments{ |
| \item{x}{the values to be matched: converted to a character vector by |
| \code{\link{as.character}}. \link{Long vectors} are supported.} |
| \item{table}{the values to be matched against: converted to a character |
| vector. \link{Long vectors} are not supported.} |
| \item{nomatch}{the (integer) value to be returned at non-matching |
| positions.} |
| } |
| \description{ |
| \code{charmatch} seeks matches for the elements of its first argument |
| among those of its second. |
| } |
| \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 \code{0} is |
| returned and if no match is found then \code{nomatch} is returned. |
| |
| \code{NA} values are treated as the string constant \code{"NA"}. |
| } |
| \value{ |
| An integer vector of the same length as \code{x}, giving the |
| indices of the elements in \code{table} which matched, or \code{nomatch}. |
| } |
| \author{ |
| This function is based on a C function written by Terry Therneau. |
| } |
| \seealso{ |
| \code{\link{pmatch}}, \code{\link{match}}. |
| |
| \code{\link{startsWith}} for another matching of initial parts of strings; |
| \code{\link{grep}} or \code{\link{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 |
| } |
| \keyword{character} |
| |