Accelerating the pace of engineering and science

# Documentation Center

• Trial Software

# strfind

Find one string within another

## Description

example

k = strfind(str, pattern) searches str for occurrences of pattern. The output, k, indicates the starting index of each occurrence of pattern in str. If pattern is not found strfind returns an empty array, []. The strfind function executes a case sensitive search.

• If str is a string, strfind returns a vector of type double.

• If str is a cell array, strfind returns a cell array of vectors of type double.

## Examples

expand all

### Find String Pattern

Define string S as follows:

```S = 'Find the starting indices of the pattern string';
```

Find the pattern in in string S.

```k = strfind(S, 'in')
```
```k =

2    15    19    45```

There are four instances of the substring, in, found in S.

Find the pattern In in string S.

```k = strfind(S, 'In')
```
```k =

[]
```

Since strfind is case sensitive, the string, In, is not found in S, k is an empty array.

Find the blank spaces in string S.

```k = strfind(S, ' ')
```
```k =

5     9    18    26    29    33    41```

There are seven occurrences of blank spaces in the string S.

### Find String in Cell Array of Strings

Define the cell array of strings, cstr, as follows:

``` cstr = {'How much wood would a woodchuck chuck';
'if a woodchuck could chuck wood?'};
```

Find the pattern, wood, in cell array cstr.

``` idx = strfind(cstr, 'wood')
```
```idx =

[1x2 double]
[1x2 double]
```

Examine the output cell array to find the instances of wood.

``` idx{:,:}
```
```ans =

10    23

ans =

6    28```

The pattern, wood, occurs at indices 10 and 23 in the first string and at indices 6 and 28 in the second string.

## Input Arguments

expand all

### str — Data to be searchedstring | cell array of strings

Data to be searched, specified as a string or cell array of strings.

Data Types: char | cell

### pattern — Search patternstring

Search pattern, specified as a string.

Data Types: char

## Output Arguments

expand all

### k — Indices of occurrences of patternarray

Indices of occurrences of pattern, returned as an array. If pattern is not found, then k is an empty array, [].

• If str is a string, k is an array of doubles indicating the index of each occurrence of pattern.

• If str is a cell array of strings, k is a cell array with each element being an array of type double corresponding to the indices of each occurrence of pattern in the corresponding element of str.