php 流程控制语句
本文章要讲到了php 两种流程判断语句,有switch语句和if else ,if()语句,下面我们来详细的看看实例吧.代码如下:
switch(variable){
case value1:
statement1;
break;
case value2:
…
default:
defulat statement;
}switch语句根据variable的值,依次与case中的value值相比较,如果不相等,继续查找下一个
case；如果相等，就执行对应的语句,直到switch语句结束或者遇见break为止.代码如下:
<?php
switch ($i) {
case "apple":
echo "i is apple";
break;
case "bar":
echo "i is bar";
break;
case "cake":
echo "i is cake";
break;
}
?>实例二代码如下:
<?php
switch ($i) {
case 0:
echo "i equals 0";
break;
case 1:
echo "i equals 1";
break;
case 2:
echo "i equals 2";
break;
}
?>实例三代码如下:
<?php
switch ($i) {
case 0:
case 1:
case 2:
echo "i is less than 3 but not negative";
break;
case 3:
echo "i is 3";
}
?>if…else语句只能选择两种结果：要么执行真，要么执行假。但现在有2种以上的选择该怎么办呢？这时,可以使用esleif（也可以写作else if）语句来执行,该语法格式为:
if(expression1){
statement1;
}else if(expression2){
statement2;
}
…
else{
statementn;
}实例代码如下:
<?php
$moth = date("n");
$today = date("j");
if ($today >= 1 and $today <= 10) {
echo '今天是' . $moth . '月' . $today . '日上旬';
} elseif ($today > 10 and $today <= 20) {
echo '今天是' . $moth . '月' . $today . '日中旬';
} else {
echo '今天是' . $moth . '月' . $today . '日下旬'；
}
?>如果当前日期是周五,下面的例子会输出 "Have a nice weekend!",如果是周日,则输出 "Have a nice Sunday!",否则输出 "Have a nice day!",代码如下:
<html>
<body>
<?php
$d = date("D");
if ($d == "Fri") echo "Have a nice weekend!";
elseif ($d == "Sun") echo "Have a nice Sunday!";
else echo "Have a nice day!";
?>
</body>
</html>文章地址:http://www.phprm.com/lckz/fs2977.html
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