Does String Start or End With Another String

startsWith

Description

Tests if a string starts or ends with a another string. The matching is literal: no regular expressions are allowed.

Usage

startsWith(x, prefix)
endsWith(x, suffix)

Arguments

x	a character vector to be matched into.
prefix	a character vector. startsWith returns TRUE when x starts with prefix.
suffix	a character vector. endsWith returns TRUE when x ends with prefix.

Details

These functions are vectorized. The inputs x and prefix (or suffix) are replicated out to the maximum length of the two arguments. Then the matching is done on each element of x with each element of prefix (or suffix).

Value

returns a logical vector with length the maximum length of the two arguments.

For startsWith, the value is TRUE if that element of x starts with the corresponding element of prefix.
For endsWith, the value is TRUE if that element of x ends with the corresponding element of prefix.

See Also

grep, substring

Examples

startsWith(c("thistle", "wheat", "maize"), "t")
## [1]  TRUE FALSE FALSE
endsWith(c("thistle", "wheat", "maize"), "e")
## [1]  TRUE FALSE  TRUE
endsWith(c("thistle", "wheat", "maize"), "ze")
## [1] FALSE FALSE  TRUE
# The matching is literal, no regular expressions are processed:
startsWith(c("one", "[a-z]", "[A-Z]"), prefix="[a-z]")
## [1] FALSE  TRUE FALSE
#  Arguments are replicated out to maximum length:
startsWith(c("A", "A", "B", "B"), prefix=c("A", "B"))
## [1]  TRUE FALSE FALSE  TRUE
endsWith("tomato", suffix=c("a", "e", "i", "o", "u"))
## [1] FALSE FALSE FALSE  TRUE FALSE

Package base version 6.1.0-42
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