Why PHP uses the Array_combine method to affect the original array

Take a look at the following code:

There are two arrays before processing arrTitle and arrHref ,

The arrTitle contents are as follows:

arrHrefThe contents are as follows:

//将title数组中首元素取出,作为栏目标题foreach ($arrTitle as &$title) {    $text [] = $title[0];    unset($title[0]);}//将href数组中首元素取出,作为栏目urlforeach ($arrHref as &$href) {    $url [] = $href[0];    unset($href[0]);}print_r($arrTitle);//重新组织title项$title = array_combine($text, $url);print_r($arrTitle);die;

Run the above PHP code to remove and remove the first element of each entry in title and href, but the problem is, before it executes array_combine $arrTitle :

After the execution array_combine , however, $arrTitle it became like this:

Why, $arrTitle the last element becomes the array_combine() result, and the array_combine() function does not modify the $arrTitle execution?

Reply content:

Take a look at the following code:

There are two arrays before processing arrTitle and arrHref ,

The arrTitle contents are as follows:

arrHrefThe contents are as follows:

//将title数组中首元素取出,作为栏目标题foreach ($arrTitle as &$title) {    $text [] = $title[0];    unset($title[0]);}//将href数组中首元素取出,作为栏目urlforeach ($arrHref as &$href) {    $url [] = $href[0];    unset($href[0]);}print_r($arrTitle);//重新组织title项$title = array_combine($text, $url);print_r($arrTitle);die;

Run the above PHP code to remove and remove the first element of each entry in title and href, but the problem is, before it executes array_combine $arrTitle :

After the execution array_combine , however, $arrTitle it became like this:

Why, $arrTitle the last element becomes the array_combine() result, and the array_combine() function does not modify the $arrTitle execution?

**$title** = array_combine($text, $url);

Here the $title and the above cycle of the $title duplicate name, change the names of the good. There is no block scope in PHP.

This bug has been lifted, thanks to @whyreal point out the duplicate name problem.

Because in the Foreach loop, to 引用方式 iterate through the array, when the loop ends, it $title points to $arrTitle the last set of elements.

Since PHP has no block-level scope, at $title = Array_combine ($arr 1, $arr 2), the $title modifies the last set of elements it points to, resulting in $arrTitle a bug.

Modify $title the name that follows to dismiss the bug.

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