# FilterIterator::key

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

FilterIterator::key — Get the current key

### 说明

public FilterIterator::key(): mixed
警告

本函数还未编写文档，仅有参数列表。

Get the current key.

### 参数

此函数没有参数。

### 返回值

The current key.

### 参见

- FilterIterator::next() - Move the iterator forward
- FilterIterator::current() - Get the current element value

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