array_keys() function returns a new array containing all the keys in the array.
Grammar
array_keys(array,value,strict)
Related recommendations:《php array》
Example
Return a new array containing all the key names in the array:
"XC90","BMW"=>"X5","Toyota"=>"Highlander"); print_r(array_keys($a)); ?>
Running result:
Array ( [0] => Volvo [1] => BMW [2] => Toyota )
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