# MongoCursor::key

(PECL mongo >=0.9.0)

MongoCursor::key — Returns the current result's _id, or its index within the result set

### Description

public MongoCursor::key ( ) : string|int

### Parameters

This function has no parameters.

### Return Values

The current result's `_id` as a string. If the result has no `_id`, its numeric index within the result set will be returned as an integer.

### See Also

- Iterator::key() - Return the key of the current element