Extract Substrings from a Character Vector

Description

Extract substrings from a character vector returning a vector whose elements contain the substring starting with the character at position start up to the character at position stop.

Usage

substr(x, start, stop)
substring(text, first, last = 1000000)

Details

If start is larger than the string length then NA is returned. If stop is longer than start an error is signalled.

substring is compatible with S, with first and last instead of start and stop. For vector arguments, it expands the arguments cyclically.

See Also

strsplit, paste, nchar.

Examples

substr("abcdef",2,4)
print(ss <- substring("abcdef",1:6,1:6))
all(  ss == strsplit ("abcdef",NULL)[[1]])# strsplit is more efficient..

substr(rep("abcdef",4),1:4,4:5)
x <- c("asfef", "qwerty", "yuiop[", "b", "stuff.blah.yech")
all(substr(x, 2, 5) == substring(x, 2, 5)) #> TRUE
substr(x, 2, 5)
substring(x, 2, 4:6)