substr {base} | R Documentation

## 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))
    stopifnot(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")
    stopifnot(substr(x, 2, 5) == substring(x, 2, 5))
    substr(x, 2, 5)
    substring(x, 2, 4:6)