How does php obtain the array key name instance code?

My php foreach () function can traverse the array and retrieve the key value of the array. How can I get the key name $ key? Or just take the first key name? For example

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$ Keyarray = array ( '000000' => '2b70e63ffdf ', '000000' => '20767a021' );

In the first method, I can use foreach to retrieve the first key name.

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Foreach ($ keyarray as $ key => $ value ){ $ A [] = $ key; } Print_r ($ a [0]); exit;

You can also use print_r ($ a); to retrieve all key names, use the array_keys () function.

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$ ArrKeys = array_keys ($ keyarray ); Print_r ($ arrKeys [0]); exit;

The above methods can achieve the same effect.