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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