# Documentation

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## Create Character Arrays

### Create Character Vector

Create a character vector by enclosing a sequence of characters in single quotation marks.

`chr = 'Hello, world';`

Character vectors are `1`-by-`n` arrays of type `char`. In computer programming, string is a frequently-used term for a `1`-by-`n` array of characters.

`whos chr`
``` Name Size Bytes Class Attributes chr 1x12 24 char ```

If the text contains a single quotation mark, include two quotation marks when assigning the character vector.

`newChr = 'You''re right'`
```newChr = You're right```

Functions such as `uint16` convert characters to their numeric codes.

`chrNumeric = uint16(chr)`
```chrNumeric = 72 101 108 108 111 44 32 119 111 114 108 100 ```

The `char` function converts the integer vector back to characters.

```chrAlpha = char([72 101 108 108 111 44 32 119 111 114 108 100]) ```
```chrAlpha = Hello, world```

### Create Rectangular Character Array

Character arrays are `m`-by-`n` arrays of characters, where `m` is not always `1`. You can join two or more character vectors together to create a character array. This is called concatenation and is explained for numeric arrays in the section Concatenating Matrices. As with numeric arrays, you can combine character arrays vertically or horizontally to create a new character array.

Alternatively, combine character vectors into a cell array. Cell arrays are flexible containers that allow you to easily combine character vectors of varying length.

#### Combine Character Vectors Vertically

To combine character vectors into a two-dimensional character array, use square brackets or the `char` function.

• Apply the MATLAB® concatenation operator, `[]`. Separate each row with a semicolon (`;`). Each row must contain the same number of characters. For example, combine three character vectors of equal length:

```devTitle = ['Thomas R. Lee'; ... 'Sr. Developer'; ... 'SFTware Corp.']; ```

If the character vectors have different lengths, pad with space characters as needed. For example:

```mgrTitle = ['Harold A. Jorgensen '; ... 'Assistant Project Manager'; ... 'SFTware Corp. ']; ```
• Call the `char` function. If the character vectors have different lengths, `char` pads the shorter vectors with trailing blanks so that each row has the same number of characters.

```mgrTitle = char('Harold A. Jorgensen', ... 'Assistant Project Manager', 'SFTware Corp.');```

The `char` function creates a `3`-by-`25` character array `mgrTitle`.

#### Combining Character Vectors Horizontally

To combine character vectors into a single row vector, use square brackets or the `strcat` function.

• Apply the MATLAB concatenation operator, `[]`. Separate the input character vectors with a comma or a space. This method preserves any trailing spaces in the input arrays.

```name = 'Thomas R. Lee'; title = 'Sr. Developer'; company = 'SFTware Corp.'; fullName = [name ', ' title ', ' company]```

MATLAB returns

```fullName = Thomas R. Lee, Sr. Developer, SFTware Corp. ```
• Call the concatenation function, `strcat`. This method removes trailing spaces in the inputs. For example, combine character vectors to create a hypothetical email address.

```name = 'myname '; domain = 'mydomain '; ext = 'com '; address = strcat(name, '@', domain, '.', ext)```

MATLAB returns

```address = myname@mydomain.com ```

### Identify Characters

Use any of the following functions to identify a character array, or certain characters in a character array.

FunctionDescription
`ischar`Determine whether the input is a character array
`isletter`Find all alphabetic letters in the input character array
`isspace`Find all space characters in the input character array
`isstrprop`Find all characters of a specific category

Find the spaces in a character vector.

```chr = 'Find the space characters in this character vector'; % | | | | | | | % 5 9 15 26 29 34 44 find(isspace(chr)) ```
```ans = 5 9 15 26 29 34 44 ```

### Work with Space Characters

The `blanks` function creates a character vector of space characters. Create a vector of 15 space characters.

```chr = blanks(15) ```
```chr = ```

To make the example more useful, append a `'|'` character to the beginning and end of the blank character vector so that you can see the output.

```['|' chr '|'] ```
```ans = | | ```

Insert a few nonspace characters in the middle of the blank character vector.

```chr(6:10) = 'AAAAA'; ['|' chr '|'] ```
```ans = | AAAAA | ```

You can justify the positioning of these characters to the left or right using the `strjust` function:

```chrLeft = strjust(chr,'left'); ['|' chrLeft '|'] ```
```ans = |AAAAA | ```
```chrRight = strjust(chr,'right'); ['|' chrRight '|']```
```ans = | AAAAA|```

Remove all trailing space characters with `deblank`:

```chrDeblank = deblank(chr); ['|' chrDeblank '|'] ```
```ans = | AAAAA|```

Remove all leading and trailing spaces with `strtrim`:

```chrTrim = strtrim(chr); ['|' chrTrim '|'] ```
```ans = |AAAAA| ```

### Expand Character Arrays

Generally, MathWorks® does not recommend expanding the size of an existing character array by assigning additional characters to indices beyond the bounds of the array such that part of the array becomes padded with zeros.