摘要：說明將所有鍵名改為全大寫或者小寫張三男張三男說明將一個(gè)數(shù)組分割成多個(gè)數(shù)組張三男張三男說明返回?cái)?shù)組中指定的一列男男女男男女說明將一個(gè)數(shù)組作鍵值，另一個(gè)數(shù)組作值產(chǎn)生一個(gè)新的數(shù)組說明數(shù)組中的鍵是中的值，數(shù)組中的值是的值出現(xiàn)的次數(shù)使用鍵名比

array_change_key_case(array $arr, [, int $case = CASE_LOWER]) : array

說明：將所有鍵名改為全大寫或者小寫

$arr = [
    "name" => "張三",
    "Age" => 18,
    "gender" => "男",
];

// case upper
print_r(array_change_key_case($arr, CASE_UPPER));
// output
Array
(
    [NAME] => 張三
    [AGE] => 18
    [GENDER] => 男
)

array_chunk ( array $array , int $size [, bool $preserve_keys = false ] ) : array
說明：將一個(gè)數(shù)組分割成多個(gè)數(shù)組

$arr = [
    "name" => "張三",
    "Age" => 18,
    "gender" => "男",
];

print_r(array_chunk($arr, 2));

// output
Array
(
    [0] => Array
        (
            [0] => 張三
            [1] => 18
        )
    [1] => Array
        (
            [0] => 男
        )
)

array_column ( array $input , mixed $column_key [, mixed $index_key = null ] ) : array
說明：返回?cái)?shù)組中指定的一列

$arr = [
    0 => [
        "name" => "LeiJian",
        "age" => 18,
        "gender" => "男",
    ],
    1 => [
        "name" => "ZhangSan",
        "age" => 19,
        "gender" => "男",
    ],
    2 => [
        "name" => "LiSi",
        "age" => 20,
        "gender" => "女",
    ],
];

print_r(array_column($arr, NULL, "name"));

// output
Array
(
    [LeiJian] => Array
        (
            [name] => LeiJian
            [age] => 18
            [gender] => 男
        )
    [ZhangSan] => Array
        (
            [name] => ZhangSan
            [age] => 19
            [gender] => 男
        )
    [LiSi] => Array
        (
            [name] => LiSi
            [age] => 20
            [gender] => 女
        )
)

array_combine ( array $keys , array $values ) : array
說明：將一個(gè)數(shù)組作鍵值，另一個(gè)數(shù)組作值產(chǎn)生一個(gè)新的數(shù)組

$a = [1, 2, 3];

$b = ["a", "b", "c"];

print_r(array_combine($a, $b));

// output
Array
(
    [1] => a
    [2] => b
    [3] => c
)

array_count_values ( array $array ) : array
說明：數(shù)組中的鍵是 array 中的值，數(shù)組中的值是 array 的值出現(xiàn)的次數(shù)

$arr = [1, "hello", 1, "world", "world"];

print_r(array_count_values($arr));

// output
Array
(
    [1] => 2
    [hello] => 1
    [world] => 2
)

array_diff_key ( array $array1 , array $array2 [, array $... ] ) : array
使用鍵名（key）比較數(shù)組的差集

$arr1 = ["first" => 2, "third" => 3, "fourth" => 4];

$arr2 = ["first" => 1, "second" => 2, "third" => 3];

print_r(array_diff_key($arr1, $arr2));

// output
Array
(
    [fourth] => 4
)

array_diff_uassoc ( array $array1 , array $array2 [, array $... ], callable $key_compare_func ) : array
說明：使用回調(diào)函數(shù)做索引檢查數(shù)組差集

$arr1 = ["first" => 2, "third" => 3, "fourth" => 4];

$arr2 = ["first" => 1, "second" => 2, "third" => 3];

print_r(array_diff_uassoc($arr1, $arr2, function($a, $b){

    if ($a === $b) {
        return 0;
    }
    
    return ($a > $b) ? 1 : -1;
}));

// output
Array
(
    [first] => 2
    [fourth] => 4
)

`array_diff ( array $array1 , array $array2 [, array $... ] ) : array
`
說明：比較數(shù)組間的差集（array1 比較數(shù)組，array2 被比較）

$arr1 = [1, 2, 3, 4, 6];

$arr2 = [2, 3, 4, 5];

print_r(array_diff($arr1, $arr2));

// output
Array
(
    [0] => 1
    [4] => 6
)

array_fill_keys ( array $keys , mixed $value ) : array
說明：使用指定鍵值（數(shù)組）和值進(jìn)行填充數(shù)組

$arr1 = [1, 2, 3, 4, 6];

print_r(array_fill_keys($arr1, "HaHaHa~"));

// output
Array
(
    [1] => HaHaHa~
    [2] => HaHaHa~
    [3] => HaHaHa~
    [4] => HaHaHa~
    [6] => HaHaHa~
)

`array_fill ( int $start_index , int $num , mixed $value ) : array
`
說明：用給定的值進(jìn)行填充數(shù)組，start_index索引開始位置，若為負(fù)值，則從 0 開始，num 為填充數(shù)量

print_r(array_fill(2, 3, "HaHaHa~"));

// output
Array
(
    [2] => HaHaHa~
    [3] => HaHaHa~
    [4] => HaHaHa~
)

array_filter ( array $array [, callable $callback [, int $flag = 0 ]] ) : array
說明：用回調(diào)函數(shù)過濾數(shù)組中的值（flag 決定 callback接收的參數(shù)）

$arr1 = [1, 2, 3, 4, 6];

print_r(array_filter($arr1, function($value){
    if ($value > 2) {
        return $value;
    }
}));

// output
Array
(
    [2] => 3
    [3] => 4
    [4] => 6
)