WP_List_Util::pluck( int|string $field, int|string $index_key = null )

Plucks a certain field out of each element in the input array.


Description

This has the same functionality and prototype of array_column() (PHP 5.5) but also supports objects.


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Parameters

$field

(int|string) (Required) Field to fetch from the object or array.

$index_key

(int|string) (Optional) Field from the element to use as keys for the new array.

Default value: null


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Return

(array) Array of found values. If $index_key is set, an array of found values with keys corresponding to $index_key. If $index_key is null, array keys from the original $list will be preserved in the results.


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Source

File: wp-includes/class-wp-list-util.php

	public function pluck( $field, $index_key = null ) {
		$newlist = array();

		if ( ! $index_key ) {
			/*
			 * This is simple. Could at some point wrap array_column()
			 * if we knew we had an array of arrays.
			 */
			foreach ( $this->output as $key => $value ) {
				if ( is_object( $value ) ) {
					$newlist[ $key ] = $value->$field;
				} else {
					$newlist[ $key ] = $value[ $field ];
				}
			}

			$this->output = $newlist;

			return $this->output;
		}

		/*
		 * When index_key is not set for a particular item, push the value
		 * to the end of the stack. This is how array_column() behaves.
		 */
		foreach ( $this->output as $value ) {
			if ( is_object( $value ) ) {
				if ( isset( $value->$index_key ) ) {
					$newlist[ $value->$index_key ] = $value->$field;
				} else {
					$newlist[] = $value->$field;
				}
			} else {
				if ( isset( $value[ $index_key ] ) ) {
					$newlist[ $value[ $index_key ] ] = $value[ $field ];
				} else {
					$newlist[] = $value[ $field ];
				}
			}
		}

		$this->output = $newlist;

		return $this->output;
	}

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Changelog

Changelog
Version Description
4.7.0 Introduced.

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User Contributed Notes

  1. Skip to note 1 content
    Contributed by shanemac10

    It looks like this error is relatively common on the Add Plugins page:
    stdClass::$plugin in .../htdocs/wp-includes/class-wp-list-util.php on line 153

    I quieted the error on my site by adding if(!empty($value->$field)) checks before calling the field. I have no idea if this is best solution, but at least it fails quietly now.

    			foreach ( $this->output as $key => $value ) {
    				if ( is_object( $value ) ) {
    					if(!empty($value->$field)) $newlist[ $key ] = $value->$field;
    				} else {
    					if(!empty($value[ $field ])) $newlist[ $key ] = $value[ $field ];
    				}
    			}

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