# containsString

Source: https://taxilang.org/docs/language/stdlib/containsString

**Full name:** `taxi.stdlib.containsString`

## Signature

```taxi
declare extension function containsString(source:String, valueToSearchFor:String):Boolean
```

## Description

Returns `true` if `source` contains `valueToSearchFor` as a substring. The match is case-sensitive.

```taxi
// Check if a description mentions a keyword
find {
   mentionsDiscount: Boolean = Description.containsString("discount")
}
```

## Examples

Checks for a case-sensitive substring match.

Query:

```taxi
find {
   hasSubstring: Boolean = "hello world".containsString("world")
   caseSensitive: Boolean = "hello world".containsString("World")
}
```

Result:

```json
{
  "hasSubstring": true,
  "caseSensitive": false
}
```