`string.lastIndexOf()`

Get the index of the last matching substring within a String.

Signature

lastIndexOf(pattern: String) => Number | Null

lastIndexOf(pattern: String, end: Number) => Number | Null

Description

Returns the zero-based offset index for the last occurrence of a provided substring within the calling String. Ends at an optional end position in the calling String.

Parameters

Parameter	Type	Required	Description
pattern	String	true	Substring to find the last occurrence of within the calling String.
end	Int	true	Zero-based index of the character to end searching for matches, counting from left to right. Defaults to the last character of the calling String.

Parameter

Type

Required

Description

pattern

String

true

Substring to find the last occurrence of within the calling String.

end

Int

true

Zero-based index of the character to end searching for matches, counting from left to right. Defaults to the last character of the calling String.

Return value

One of:

Type	Description
Int	Zero-based index of the last matching occurrence in the calling String, ending at the specified end character.
Null	No match not found.

Type

Description

Int

Zero-based index of the last matching occurrence in the calling String, ending at the specified end character.

Null

No match not found.

Examples

Get the location of the last occurrence of the String "200" at or below index location 27:
```
"HTTP/1.1 200 OK - SUCCESS (200)".lastIndexOf("200", 27)
```
```
27
```
Get the location of the last occurrence of the String "200" at or below index location 20:
```
"HTTP/1.1 200 OK - SUCCESS (200)".lastIndexOf("200", 20)
```
```
9
```
Get the location of the last occurrence of the String "200" at or below index location 8, which fails because the String isn’t found:
```
"HTTP/1.1 200 OK - SUCCESS (200)".lastIndexOf("200", 8)
```
```
null
```