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法律研究如何在 PHP 中根据键删除数组元素？
要删除 PHP 中基于键的数组元素，代码如下：
示例
<?php $arr = array( " John ", "Jacob ", " Tom ", " Tim "); echo "Array with leading and trailing whitespaces...
"; foreach( $arr as $value ) { echo "Value = $value
"; } echo "
Comma separated list...
"; print_r(implode(', ', $arr)); $result = array_map('trim', $arr); echo "
Updated Array...
"; foreach( $result as $value ) { echo "Value = $value
"; } unset($result[1]); echo "
Updated Array...
"; foreach( $result as $value ) { echo "Value = $value
"; } ?>
输出
这将产生以下输出：
Array with leading and trailing whitespaces... Value = John Value = Jacob Value = Tom Value = Tim Comma separated list... John , Jacob , Tom , Tim Updated Array... Value = John Value = Jacob Value = Tom Value = Tim Updated Array... Value = John Value = Tom Value = Tim
示例
我们现在来看另一个示例：
<?php $marks = array( "kevin" => array ( "physics" => 95, "maths" => 90, ), "ryan" => array ( "physics" => 92, "maths" => 97, ), ); echo "Marks for kevin in physics : " ; echo $marks['kevin']['physics'] . "
"; echo "Marks for ryan in maths : "; echo $marks['ryan']['maths'] . "
"; unset($marks["ryan"]); echo "Marks for ryan in maths : "; echo $marks['ryan']['maths'] . "
"; ?>
输出
这将产生以下输出。现在，将显示一条错误，因为我们删除了元素并尝试访问它：
Marks for kevin in physics : 95 Marks for ryan in maths : 97 Marks for ryan in maths : PHP Notice: Undefined index: ryan in /home/cg/root/6985034/main.php on line 25
更新于： 2019 年 12 月 27 日
693 次浏览
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