Question

How to use array_keys() function to return the keys from array in PHP

Answer 1

$arr = array("a" => "PHP", "b"=>"C++", "y"=>"C");

print_r(array_keys($arr));
  
/*
run:
  
Array ( [0] => a [1] => b [2] => y ) 
       
*/

 

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Answer 2

$arr = array("a"=>"PHP", "b"=>"C++", "y"=>"C", "q"=>"PHP");

print_r(array_keys($arr, "PHP"));
  
/*
run:
  
Array ( [0] => a [1] => q )
       
*/

 

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Answer 3

$arr = array(1, 2, 3, 4, 5, "1");

// false - default - not depending on type: 1 == "1"
print_r(array_keys($arr, "1", false));
  
/*
run:
  
Array ( [0] => 0 [1] => 5 ) 
       
*/

 

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Answer 4

$arr = array(1, 2, 3, 4, 5, "1");

// true - depending on type: 1 != "1"
print_r(array_keys($arr, "1", true));
  
/*
run:
  
Array ( [0] => 5 ) 
       
*/

 

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