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

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Description

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

Usage

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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

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## 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

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