php中,一共提供了以下循环语句:
while循环将重复执行代码块,直到指定的条件不成立。 语法:
while (条件)
{
要执行的代码;
}
示例:
<?php
$i=1;
while($i<=5)
{
echo "the number is " . $i . "<br>";
$i++;
}
?>
结果:
the number is 1
the number is 2
the number is 3
the number is 4
the number is 5
do…while循环会先执行一次代码,然后检查条件是否成立,只要条件成立,就会开始循环。
语法:
do{
要执行的代码;
}
while(条件);
示例:
<?php
$i=1;
do
{
echo "the number is " . $i . "<br>";
}
while($i<=5);
?>
结果:
the number is 1
the number is 2
the number is 3
the number is 4
the number is 5
for循环一般用于预先知道需要循环次数的情况下
语法:
for (初始值;条件;增量;)
{
要执行的代码;
}
参数:
示例:
<?php
for ($i=1;$<=5;$i++)
{
echo "number is " . $i . "<br>";
}
?>
结果:
number is 1
number is 2
number is 3
number is 4
number is 5
foreach用于遍历数组
语法:
foreach ($array as $vaule)
{
要执行的代码;
}
每进行一次循环,当前数组元素的值就会被赋值给 $value 变量(数组指针会逐一地移动),在进行下一次循环时,您将看到数组中的下一个值。
示例:
<?php
$i=["one","two","three"];
foreach ($i as $vaule)
{
echo $vaule . "<br>";
}
?>
结果:
one
two
three