常用字符串操作函数_2018-08-29_8:40上传

作业代码：

实例

<?php
echo "<h3>编程1： 实例演示substr(),strstr(),strpos()函数</h3><hr />";
$str="My name is staroom";
echo "<h4>substr()</h4>";
echo "<p>My name is staroom <br />取前两位:",substr($str,0,2),"，取后7位：",substr($str,-7),",从第3开始，取4位：",substr($str,3,4),"</p>";
echo "<h4>strstr()</h4>";
echo "<p>
查询name是否存在，返回name及后面内容：",strstr($str,"name"),",返回前面内容：",strstr($str,"name",true),"
</p>";
echo "<h4>strpos()</h4>";
echo "<p>
查询star首次出现的位置：",strpos($str,"star"),"
</p><hr />";
echo "<h3>编程2: 实例演示str_replace(), substr_replace()</h3><hr />";
$strs="My name is staroom. Staroom is a chinese";
echo "<h4>str_replace() str_ireplace()</h4>";
echo $strs,"<br />";
echo "<p>
替换staroom：",str_replace("staroom","Yuxicheng",$strs),"<br />忽略大小写:",str_ireplace("staroom","Yucicheng",$strs),"
</p>";
echo "<h4>sustr_replace()</h4>";
echo "<p>
从第20位开始替换：",substr_replace($strs,"I come from Hubei,China.",20),"
</p><hr />";
echo "<h3>编程3: 实例演示: usort()二维数组的排序</h3><hr />";
echo "<pre>";
$array=[[ "name"=>"张三","steps"=>20122],["name"=>"李四","steps"=>10982],["name"=>"王五","steps"=>18902]];
echo "原始：",var_dump($array),"<br />";
usort($array,function($n,$m){
  return $m['steps']<$n['steps'];
});

echo "步数大小到大:<br />";
var_dump($array);
 ?>