php去掉一维数组的键值的实例方法

在 PHP 中，数组的每个元素都是由键值对（key-value）组成，通过元素的键名来访问对应键的值。

提示：“索引”和“键名”指的是同一样东西，“索引”多指数组数字形式的下标。

有时候，我们需要去掉一维数组的键值（value），只留下数组的键名（key），这要怎么做？

此时，就可以使用array_keys()函数了。

array_key() 函数可以获取数组中的部分或所有键名，语法格式如下：

array_keys($array [, $search_value = null [, $strict = false]])

参数说明如下：

$array：必选参数，为待操作的数组；

$search_value：可选参数，如果参数为空，则函数会返回数组中的所有键名，如果指定了该参数，则函数就只会返回值为 $search_value 的键名；

$strict：可选参数，判断在搜索的时候是否使用严格模式，$strict 默认为 false，也就是非严格模式，在搜索时只比较类型，不比较类型，若将 $strict 设置为 true，也就是严格模式，在搜索时同时比较值和类型，等价于===。

array_key() 函数会以数组形式返回得到的数组键名。

 '好二三四it网',        'url'   => 'https://www.how234.com/',        'title' => 'PHP学习教程',);$key=array_keys($array);var_dump($key);?>

可以看到，去掉了一维数组的键值（value），只返回了一维数组的键名（key）。

内容扩展：

1、使用unset()函数可以用于取消设置关联数组中的键及其值。

// 声明关联数组$arr = array(    "1" => "加",    "2" => "减",    "3" => "乘",    "4" => "除");// 关联数组中删除键1及其值unset($arr['1']);// 显示数组元素var_dump($arr);

2、使用array_diff_key()函数用于获取一个或多个数组之间的差集。

此函数比较一个或多个数组之间的键并返回它们之间的差集。

// 声明关联数组$arr = array(    "1" => "春",    "2" => "夏",    "3" => "秋",    "4" => "冬",);// 从关联数组中删除键1及其值$result = array_diff_key($arr,    array_flip((array) ['1']));// 显示数组元素var_dump($result);

到此这篇关于php去掉一维数组的键值的实例方法的文章就介绍到这了。

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