for loop
##Format: for($i=0;$i<10;$i++){
Execute code
}
Now make a case of the sum of 1+2+....10
<?php
header("Content-type: text/html; charset=utf-8");//设置编码
//计算1到10之和
$sum = 0 ; //定义一个变量 初始值为0
for($i=1;$i<=10;$i++){ //进入循环，当$i是1时，满足条件，执行$i++
$sum = $sum + $i;
}
echo $sum;
?>while loop
Format: while (condition){
Execution code;
}
Use the while loop to calculate the number between 1 and 10 And
<?php
//while 循环 1到10 之和
$sum = 0;
$i = 1;
while($i<=10){
$sum = $sum + $i;
$i++; //如果没有$i++ 那么$i的值就不会发生变化，这样就会一直循环
}
echo $sum;
?>do....while loop
##Format: do{
Execution statement;
}while(condition);
Use do....while to realize the sum of 1 to 10
<?php
//do......while 循环 写出1到10 之和
$sum = 0 ;
$i = 1;
do{
$sum = $sum +$i;
$i++;
}while($i<=10);
echo $sum;
?>Note:
No matter whether $i meets the condition or not , the loop body will be executed once. When i = 10, enter the loop body and execute $i++. At this time, the value of $i is 11 and then enter the conditional judgment. If the condition is not met, jump out of the loop
for break and continue statements in the loop
<?php
//for 循环中break 与continue 的区别
//当使用break的时候，$i的值是5的时候就跳出循环体
//使用continue的时候，只有$i是5的时候跳出循环
for ($i=1;$i<=10;$i++){
if($i==5){
break;
//continue;
}
echo $i."</br>";
}
?>
foreach loop (emphasis)
The foreach loop is used to traverse the array.
Format: foreach($array as $value){
Execution code;
}
<?php
//foreach 循环
$arr = array('one','two','three','four','five'); //创建一个数组，里面有5个元素
foreach ($arr as $val) {
echo $val."</br>";
}
?>
Note: Each cycle is performed. The values in the array will be assigned to the $val variable (the array pointer will move one by one). When you perform the next loop, you will see the next value in the array
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