Differences in usage between loop statements foreach and list-PHP Tutorial-php.cn

Differences in usage between loop statements foreach and list

伊谢尔伦

Release： 2023-03-11 08:10:02

Original

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Generally foreach is used more often

<?php 
$price=array(&#39;apple&#39;=>10,&#39;orange&#39;=>20,&#39;banner&#39;=>30); 
foreach($price as $key=>$value) 
{ 
echo $key.&#39;=>&#39;.$value.&#39;<br>&#39;; 
} 
echo &#39;<br>&#39;; 
?>

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There is also a more advanced and common method

<?php 
$shuiguo=array(&#39;apple&#39;=>10,&#39;orange&#39;=>20,&#39;banner&#39;=>30); 
while(list($changpin,$jiage)=each($shuiguo)) 
{ 
echo "$changpin=>$jiage".&#39;<br>&#39;; 
} 
?>

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list() function can be used to decompose an array into a series The value of , allows the new variable to be named. If you don’t understand lists, click here. The output of the two pieces of code is the same.

It should be noted that when using the each() function, the array will record the current element. If you want to use the array twice in the same script. You need to use reset() to reset the current element to the beginning of the array.

<?php 
$price=array(&#39;apple&#39;=>10,&#39;orange&#39;=>20,&#39;banner&#39;=>30); 
foreach($price as $key=>$value) 
{ 
echo $key.&#39;=>&#39;.$value.&#39;<br>&#39;; 
} 
echo &#39;<br>&#39;; 
reset($price); 
while(list($key,$value)=each($price)) 
{ 
echo "$key=>$value","<br>"; 
} 
?>

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This way you can still use the array $price.
There are some in the book. As a novice, I do it myself, type it to see the effect, understand it, and write a post, so that I forget to read it in the future. It is relatively superficial, the language is not good, and it is ridiculous.

<?php 
/* 
*PHP中的循环语句学习笔记 
*一.
while循环
 
if(表达式) 
只执行一次一条语句。 
while(表达式){ 
反复执行这个循环体； 
} 
*二.do-while循环 
*三.for循环 
*根据循环条件不同有两种类型的循环 
*一种：计数循环 for 
*另外一种：条件型循环 while do-while //foreach 
*几个和循环有关的语句 
*break;//可以用于
流程控制
和循环体，跳出循环。 
continue;//只能用于循环体，退出本次循环。 exit; 
return; 
*写循环尽量不要超过三层。 
*循环的流程
控制语句
尽量不要超过五层。 
*/ 
$num=0; 
while($num<100){ 
echo "这是执行第 {$num} 次输出的结果<br>"; 
$num++; 
} 
// 
echo &#39;<table border="1" width="800" 
align="center">&#39;; 
echo &#39;<caption><h1>使用一个while循环输 
出的表格</h1></caption>&#39;; 
$i=0; 
while($i<1000){ 
if($i%10==0){ 
if($i%20==0){ 
$bg="#ffffff"; 
}else{ 
$bg="#cccccc"; 
} 
echo &#39;<tr 
onmouseover
="lrow(this)" onmouseout="drow 
(this)" bgColor="&#39;.$bg.&#39;">&#39;; 
} 
echo &#39;<td>&#39;.$i.&#39;</td>&#39;; 
$i++; 
if($i%10==0){ 
echo &#39;</tr>&#39;; 
} 
} 
echo &#39;</table>&#39;; 
// 
$i=0; 
do{ 
echo "$i :this is do*while <br>"; 
$i++; 
}while($i<10); 
// 
for(初始化的条件;条件表达式;增量){ 
循环体； 
} 
/* 
do-while循环就是先执行一次代码，然后判断，而 
while循环就是先判断，如果为true就继续循环，为 
false就不循环。 
*/ 
//
九九乘法表
 
for($i=1; $i<=9; $i++){ 
for($j=1; $j<=$i; $j++){ 
echo "$j x $i = 
".$j*$i."  "; 
} 
echo &#39;<br>&#39;;

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