classic example1

  1  
  2 
  3 <?php
  4 //1.连接一个heredoc定义的字符串
  5 $html = <<<END
  6 <div class = "divClass">
  7 <ul class = "ulClass">
  8 <li>
  9 END
 10 ."the list item"."</li></div>";
 11 
 12 echo $html;
 13 
 14  
 15 
 16 结果:   the list item
 17 
 18  
 19 
 20 //2.用strpos()来查找字符串,strpos必须用===或者!==,因为如果找到字符串,会返回开始处位置,值为0.
 21 $email = "cccccc#cc.cc";
 22 if(strpos($email,‘@‘) === false){
 23 echo ‘there was no @ in the e-mail address!‘;
 24 }
 25 
 26 结果: there was no @ in the e-mail address!
 27 
 28  
 29 
 30 //3.用substr()来提取一个子字符串
 31 echo "<br/>";
 32 $string = ‘watch out for that tree‘;
 33 $start = -17;
 34 $length = 5;
 35 $substring = substr($string,$start,$length);
 36 echo $substring;
 37 
 38 结果:out f
 39 
 40  
 41 
 42 //4.用substr_replace()替换自字符串
 43 //把从位置$start开始到$sold_string结尾处的所有字符
 44 //替换成$new_substing
 45 //$new_string = substr_replace($old_string,$new_substring,$statr);
 46 echo "<br/>";
 47 echo substr_replace(‘my pet is a blue dog.‘,‘fish‘,‘12‘);
 48 
 49 //把从$start位置开始的$length个字符替换成$new_substring
 50 //$new_srting = substr_replace($old_string,$new_substring,$start,$length);
 51 echo "<br/>";
 52 echo substr_replace(‘my pet is a blue dog.‘,‘green‘,‘12‘,4);
 53 
 54 结果:  my pet is a fish
 55 
 56 my pet is a green dog.
 57 
 58  
 59 
 60 //5.处理字符串中每一个字节
 61 
 62 echo "<br/>";
 63 $string = "this weekend,I‘m going shoping for a pet chicken";
 64 $vowels = 0;
 65 for ($i = 0,$j = strlen($string);$i < $j; $i++){
 66 if(strstr(‘aeiouAEIOU‘,$string[$i])){
 67 $vowels++;
 68 }
 69 }
 70 echo $vowels;
 71 
 72 结果: 14
 73 
 74  
 75 
 76 //6."Look and say"序列
 77 echo "<br/>";
 78 function lookandsay($s){
 79 //将保存返回值的变量初始化为空字符串
 80 $r = ‘‘;
 81 //$m用于保存我们要查找的字符
 82 //同时将其初始化为字符串中的第一个字符串
 83 $m = $s[0];
 84 
 85 //$n用于保存我们找到的$m的数目,将其初始化为1
 86 $n = 1;
 87 for($i = 1;$j = strlen($s),$i < $j;$i++){
 88 //如果这个字符与上一个字符相同
 89 if($s[$i] == $m){
 90 //这个字符的数目加1
 91 $n++;
 92 }else{
 93 //否则,把数目和这个字符追加到返回值
 94 $r .=$n.$m;
 95 //把要找的字符串设置为当前的字符
 96 $m = $s[$i];
 97 //并把数目重置为1
 98 $n = 1;
 99 }
100 }
101 //返回构建好的字符串以及最终的数目和字符
102 return $r.$n.$m;
103 }
104 for($i = 0,$s = 1;$i < 10; $i++){
105 $s = lookandsay($s);
106 echo "$s <br/>\n";
107 }
108 
109 结果:
110 
111 1 
112 11 
113 21 
114 1211 
115 111221 
116 312211 
117 13112221 
118 1113213211 
119 31131211131221 
120 13211311123113112211 
121 
122 //7.按字反转字符串
123 echo "<br/>";
124 $s = "Once upon a time there was a turtle.";
125 $words = explode(‘ ‘,$s);
126 $words = array_reverse($words);
127 $s = implode(‘ ‘,$words);
128 echo $s;
129 
130 结果: turtle. a was there time a upon Once
131 
132  
133 
134 //8.简化后按字翻转字符串的代码
135 echo "<br/>";
136 $z = "this is a dog.";
137 $reversed_s = implode(‘ ‘,array_reverse(explode(‘ ‘,$z)));
138 echo $reversed_s;
139 
140  
141 
142 结果: dog. a is this
143 
144 ?>