R: Determine if a character string "starts with" with the...

startsWith {gdata} | R Documentation

## Determine if a character string "starts with" with the specified characters.

### Description

Determine if a character string "starts with" with the specified characters.

### Usage

    startsWith(str, pattern, trim=FALSE, ignore.case=FALSE)

### Arguments

`str` | character vector to test
`pattern` | characters to check for
`trim` | Logical flag indicating whether leading whitespace should be removed from `str` before testing for a match.
`ignore.case` | Logical flag indicating whether case should be ignored when testing for a match.

### Details

This function returns TRUE for each element of the vector `str` where `pattern` occurs at the beginning of the string. If `trim` is TRUE, leading whitespace is removed from the elements of `str` before the test is performed. If `ignore.case` is TRUE, character case is ignored.

### Value

Boolean vector of the same length as `str`.

### Author(s)

Gregory R. Warnes greg@warnes.net

### See Also

`substr`, `trim`

### Examples

    ## simplest example:
    startsWith( 'Testing', 'Test')

    ## vector examples
    s <- c('Testing', ' Testing', 'testing', 'Texting')
    names(s) <- s

    startsWith(s, 'Test')                   # ' Testing', 'testing', and 'Texting' do not match
    startsWith(s, 'Test', trim=TRUE)        # Now ' Testing' matches
    startsWith(s, 'Test', ignore.case=TRUE) # Now 'testing' matches

[Package gdata version 2.18.0 Index]