假設目前有陣列

$fruits = [
    ['id'=>0,'fruit'=>'apple','sweetness'=>2],
    ['id'=>1,'fruit'=>'banana','sweetness'=>4],
    ['id'=>2,'fruit'=>'grape','sweetness'=>5],
    ['id'=>3,'fruit'=>'orange','sweetness'=>1],
];

array_column

array_column(陣列變數, key名稱(想取得的column的key) , 返回新陣列的key(可填可不填));

print_r(array_column($fruits,'fruit'));

print_r(array_column($fruits,'fruit','sweetness'));

array_keys

取得陣列的key

print_r(array_keys($fruits[0]));

print_r(array_keys($fruits));

array_values

取得陣列的value

print_r(array_values($fruits));