# Documentation

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# `substring`

Extract a substring from a string

MATLAB live scripts support most MuPAD functionality, though there are some differences. For more information, see Convert MuPAD Notebooks to MATLAB Live Scripts.

## Syntax

```substring(`string`, `i`)
substring(`string`, `i`, `l`)
substring(`string`, `i .. j`)
```

## Description

`substring(string, i)` returns the i-th character of a string.

`substring(string, i, l)` returns the substring of length `l` starting with the i-th character of the string.

`substring(string, i..j)` returns the substring consisting of the characters i through j, inclusive.

The empty string `""` is returned if the length ```l = 0``` is specified.

`substring` is considered obsolete. You should use index access to strings instead.

## Examples

### Example 1

We extract individual characters from a string:

`substring("123456789", i) \$ i = 1..9`

Substrings of various lengths are extracted:

`substring("123456789", 1, 2), substring("123456789", 4, 4)`

Substrings of length 0 are empty strings:

`substring("123456789", 4, 0)`

Ranges may be used to specify the substrings:

`substring("123456789", 1..9)`

### Example 2

The following `while` loop removes all trailing blank characters from a string:

```string := "MuPAD ": while substring(string, length(string)) = " " do string := substring(string, 1..length(string) - 1) end_while```

## Parameters

 `string` A nonempty character string `i` An integer between `1` and `length(string)` `l` An integer between `1` and `length(string)` `j` An integer between `i` and `length(string)`

Character string