From 708f73ccc91d8b83970a7aa4d0e07e39a5f1a892 Mon Sep 17 00:00:00 2001
From: Andrew Nacin <wp@andrewnacin.com>
Date: Sun, 29 Jun 2014 21:26:17 +0000
Subject: [PATCH] =?UTF-8?q?Add=20index=20key=20support=20for=20wp=5Flist?=
 =?UTF-8?q?=5Fpluck(),=20=C3=A0=20la=20array=5Fcolumn().?=
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props trepmal.
fixes #28666.

Built from https://develop.svn.wordpress.org/trunk@28900


git-svn-id: http://core.svn.wordpress.org/trunk@28699 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/functions.php | 44 ++++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 94d6de3eb5..bee66303df 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2882,21 +2882,51 @@ function wp_list_filter( $list, $args = array(), $operator = 'AND' ) {
 /**
  * Pluck a certain field out of each object in a list.
  *
+ * This has the same functionality and prototype of
+ * array_column() (PHP 5.5) but also supports objects.
+ *
  * @since 3.1.0
  *
  * @param array $list A list of objects or arrays
  * @param int|string $field A field from the object to place instead of the entire object
+ * @param int|string $index_key A field from the object to use as keys for the new array
  * @return array
  */
-function wp_list_pluck( $list, $field ) {
-	foreach ( $list as $key => $value ) {
-		if ( is_object( $value ) )
-			$list[ $key ] = $value->$field;
-		else
-			$list[ $key ] = $value[ $field ];
+function wp_list_pluck( $list, $field, $index_key = null ) {
+	if ( ! $index_key ) {
+		// This is simple. Could at some point wrap array_column()
+		// if we knew we had an array of arrays.
+		foreach ( $list as $key => $value ) {
+			if ( is_object( $value ) ) {
+				$list[ $key ] = $value->$field;
+			} else {
+				$list[ $key ] = $value[ $field ];
+			}
+		}
+		return $list;
 	}
 
-	return $list;
+	// 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.
+	$newlist = array();
+	foreach ( $list 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 ];
+			}
+		}
+	}
+
+	return $newlist;
 }
 
 /**