PHP array merge array_merge and array addition

In our actual PHP project development, array merging is one of the commonly used operations.array_merge()The function can merge one or more arrays into one array. If two or more array elements have the same key name, the last element overwrites the others. If it is an integer subscript, it will be rearranged and will not be overwritten. When adding arrays, the first one is retained and the last one is discarded. If there are identical integers in the following table, the ones that appear first will be retained, those that appear later will be discarded, and then the subscripts will be rearranged.

$programmer1 = array("a"=>"PHP程序员","b"=>"JAVA程序员","IOS程序员"); $programmer2 = array("c" =>"安卓程序员","d" => "ASP程序员","前端","a"=> "DBA");

Use array_merge() function

$programmer3 = array_merge($programmer1,$programmer2); var_dump($programmer3); array(6) { ["a"]=> string(3) "DBA" ["b"]=> string(13) "JAVA程序员" [0]=> string(12) "IOS程序员" ["c"]=> string(15) "安卓程序员" ["d"]=> string(12) "ASP程序员" [1]=> string(6) "前端" }

Use number

$programmer4 = $programmer1 + $programmer2; var_dump($programmer4); array(5) { ["a"]=> string(12) "PHP程序员" ["b"]=> string(13) "JAVA程序员" [0]=> string(12) "IOS程序员" ["c"]=> string(15) "安卓程序员" ["d"]=> string(12) "ASP程序员" }

When using array_merge to merge, the subscript is a The end result is that the DBA appears in $programmer2, and the numeric subscripts in $programmer1 and $programmer2 are rearranged and not overwritten, with the values of the two numeric subscripts. When adding and merging two arrays, the final result with subscript a is the PHP programmer appearing in $programmer1, and the integer subscript has only one IOS programmer in $programmer1, and the subscripts will also be rearranged.

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