How to use php while loop

* while loop

* 1. Entry judgment: while(condition){ #code }

* 2. Exit judgment: do { #code } while(condition)

echo &#39;<h3>while循环</h3><hr color="green">&#39;;
for ($i=0; $i<10; $i++) {
echo $i<9 ? $i.&#39;,&#39; : $i;
}
echo &#39;<hr>&#39;;

//Use while to implement the above functions

//1. Entry judgment: judge whether the condition is successful before entering the loop, it is possible not to do it once

$i = 0; //初始条件
// $i = 10; //初始条件改为10,一次都不会执行
while ($i<10) {  //循环条件
echo $i<9 ? $i.&#39;,&#39; : $i;
$i++;  //更新条件,如果没有将进和死循环
}
echo &#39;<hr>&#39;;

//2 .Exit judgment: judge whether the condition is successful after the loop execution ends, and execute the loop body at least once

$i = 0; //初始条件
// $i = 10; //初始条件改为20,但仍会执行一次
do { 
echo $i<9 ? $i.&#39;,&#39; : $i;
$i++;  //更新条件,如果没有将进和死循环
} while ($i<10);  //循环条件