php之数组
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数组分类:
1.索引数组. 索引值从0开始,依次递增。
2.使用array()函数声明数组
<?php // 1.直接为数组元素赋值即可声明数组 $contact_index[0] = 1; $contact_index[1] = "高某"; $contact_index[2] = "A公司"; $contact_index[3] = "北京市"; $contact_index[] = "[email protected]"; var_dump($contact_index); $contact_key["ID"] = "2"; $contact_key["姓名"] = "峰某"; $contact_key["公司"] = "B公司"; $contact_key["邮箱"] = "[email protected]"; var_dump($contact_key); // 2.使用array()函数声明数组 $contact_key_array = array( "ID" => 1; "姓名" => "峰某"; "公司" => "B公司"; "邮箱" => "[email protected]"; ); var_dump($contact_key_array); ?>
数组的遍历:
1.for语句遍历数组
2.foreach语句遍历数组
<?php //用for语句遍历数组 $cars=array("Volvo","BMW","SAAB"); $arrlength=count($cars); for($i=0;$i<$arrlength;$i++) { echo $cars[$i]; echo "<br>"; } ?> <?php
//foreach语句遍历关联数组 $age=array("Bill"=>"35","steve"=>"37","peter"=>"43"); foreach($age as $x=>$x_value) { echo "Key=".$x.", Value=".$x_value; echo "<br>"; } ?>
预定义数组
1.它就是一个特殊数组,操作方式没有区别。
2.不用声明它们,每个php脚本中默认存在。
3.它们在全局范围内自动生效。
预定义数组 说明
$_SERVER 变量由web服务器设定或者直接与当前脚本的执行环境相关联
$_ENV 执行环境提交至脚本的变量
$_GET 经由URL请求提交至脚本的变量
$_POST 经由HTTP POST 方法提交至标本的变量
$_REQUEST 经由GET,POST,COOKIE机制提交至脚本的变量
$_FILES 经由HTTP POST 文件上传而提交至脚本的变量
$_COOKIE 经由HTTP Cookie 方法提交至脚本的变量
$_SESSION 当前注册给脚本会话的变量
$_GLOBALS 包含一个引用指向每个当前脚本的全局范围内的有效的变量,该数组的键名 为全局变量的名称。
合并数组
array_merge()函数将数组合并到一起,返回一个联合的数组。
array array_merge(array array1 array2.....arrayN)
<?php $fruits=array("apaple","banana","pear"); $numbered=array("1","2","3"); $cards=array_merge($fruits,$numbered); print_r($cards);
// output
//Array ( [0] => apaple [1] => banana [2] => pear [3] => 1 [4] => 2 [5] => 3 )
?>
拆分数组
array_slice()函数将返回数组中的一部分,从键offset开始,到offset+length位置结束
array array_slice(array array,int offset,[int length])
offset 为正值时从前面开始,为负数时从后面开始
<?php $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon","Watermelon"); $subset=array_slice($fruits,3); print_r($subset);
//output
//Array ( [0] => Pear [1] => Grape [2] => Lemon [3] => Watermelon ) ?>
<?php
$fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon","Watermelon");
$subset=array_slice($fruits,2,-2);
print_r($subset);
//output
//Array ( [0] => Orange [1] => Pear [2] => Grape )
?>
数组头添加元素:
array_unshift函数在数组头添加元素
<?PHP $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon"); array_unshift($fruits,"AAAA","BBBB"); print_r($fruits); //output //Array ( [0] => AAAA [1] => BBBB [2] => Apple [3] => Banana [4] => Orange [5] => Pear [6] => Grape [7] => Lemon ) ?>
数组头删除元素:
array_shift删除数组头元素
<?php $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon"); array_shift($fruits); print_r($fruits); //output //Array ( [0] => Banana [1] => Orange [2] => Pear [3] => Grape [4] => Lemon ) ?>
数组尾部添加元素:
array_push函数在数组尾部添加元素
<?php $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon"); array_push($fruits,"AAAA","BBBB"); print_r($fruits); //output //Array ( [0] => Apple [1] => Banana [2] => Orange [3] => Pear [4] => Grape [5] => Lemon [6] => AAAA [7] => BBBB ) ?>
数组尾部删除元素:
array_pop函数删除数组尾部元素,返回的是数组的最后一个元素。
<?php $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon"); $result=array_pop($fruits); print_r($result); echo "<br>"; print_r($fruits); //output //$result 返回Lemon //$fruits 返回Array ( [0] => Apple [1] => Banana [2] => Orange [3] => Pear [4] => Grape ) ?>
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