Documentation

Searching and Replacing

MATLAB® provides several functions for searching and replacing characters in a string. (MATLAB also supports search and replace operations using regular expressions. See Regular Expressions.)

Consider a string named `label`:

`label = 'Sample 1, 10/28/95';`

The` ``strrep` function performs the standard search-and-replace operation. Use `strrep` to change the date from `'10/28'` to `'10/30'`:

```newlabel = strrep(label, '28', '30') newlabel = Sample 1, 10/30/95```

`strfind` returns the starting position of a substring within a longer string. To find all occurrences of the string `'amp'` inside `label`, use

```position = strfind(label, 'amp') position = 2```

The position within `label` where the only occurrence of `'amp'` begins is the second character.

The `textscan` function parses a string to identify numbers or substrings. Describe each component of the string with conversion specifiers, such as `%s` for strings, `%d` for integers, or `%f` for floating-point numbers. Optionally, include any literal text to ignore.

For example, identify the sample number and date string from `label`:

```parts = textscan(label, 'Sample %d, %s'); parts{:} ans = 1 ans = '10/28/95'```

To parse strings in a cell array, use the `strtok` function. For example:

```c = {'all in good time'; ... 'my dog has fleas'; ... 'leave no stone unturned'}; first_words = strtok(c)```