substr

Gamma: Version 4.0
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# `substr`

`substr` -- returns a substring for a given location.

## Syntax

    substr (string, start_char, length)

## Arguments

`string`

  A string.

`start_char`

  The position number of the first character of the substring.

`length`

  The length of the substring.

## Returns

A new string which is a substring of the input `string`.

## Description

This function returns a substring of the input string starting at the `start_char` position and running for `length` characters. The first character in the string is numbered zero. If `start_char` is greater than the length of the string, the function returns an empty string. If `start_char` is negative, it is indexed from the end of the string. If it is negative and greater than the length of the string, it is treated as zero--the beginning of the string.

If there are fewer characters than `length` in the string, or if `length` is -1, then the substring contains all characters from `start_char` to the end of the string.

## Example

        Gamma> substr("Acme widgets",7,3);
        "dge"
        Gamma> substr("Acme widgets",9,-1);
        "ets"
        Gamma> substr("Acme widgets",-7,4);
        "widg"
        Gamma> substr("Acme widgets",-30,4);
        "Acme"
        Gamma>

## See Also

`strchr`, `strrchr`, `string`, `strstr`

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