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php 常用字符串函数总结
print,echo,printf(),sprintf():echo()不是函数,print()是函数,有返回值,boolen,false,true;printf()格式化输
1.格式化输出
chop 是rtrim()的别名;
ltrim()
trim()
nl2br()将\n转换成<br>
print,echo,printf(),sprintf():
echo()不是函数,print()是函数,有返回值,boolen,false,true;
printf()格式化输出
--函数,把文字格式化以后输出,直接调用系统调用进行IO的,他是非缓冲的。如:
$name="hunte";
$age=25;
printf("my name is %s, age %d", $name, $age);
sprintf()格式化字符串,然后赋给一个变量,但是不输出,类似于c了
<"foo isn't\n bar"); echo "foo isn't\n bar"; "select * from table where no = '%s'",bankno);
它的功能只是把""里面的语句赋给了变量sql。strtolower
strtoupper
ucwords
ucfirst2.字符串的连接和分割
(1)array explode(string input ,string separator , int limit)
使用一个字符串分割另一个字符串
<"piece1 piece2 piece3 piece4 piece5 piece6"; $pieces = explode(" ", $pizza); echo $pieces[0]; // piece1 echo $pieces[1]; // piece2 // 示例 2 $data = "foo:*:1023:1000::/home/foo:/bin/sh"; list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data); echo $user; // foo echo $pass; // * "htmlcode"><"htmlcode"><"This is\tan example\nstring"; /* Use tab and newline as tokenizing characters as well */ $tok = strtok($string, " \n\t"); //拿着空格,\n,\t作为令牌分割字符串 while ($tok !== false) { echo "Word=$tok<br />"; $tok = strtok(" \n\t"); } "htmlcode">$test="Your customer service is excellent"; echo substr($test,1);////////our customer service is excellent echo "<br>"; echo substr($test,-9);//////从末尾起长度是9excellent echo "<br>"; echo substr($test,0,4);////从0位置开始长度是4Your echo "<br>"; echo substr($test,5,-13);/从第四个开始到倒数第13个字符customer service echo "<br>"; $test="Your customer service is excellent"; echo substr($test,1); echo "<br>"; echo substr($test,-11); echo "<br>"; echo substr($test,0,6); echo "<br>"; echo substr($test,5,-13); echo "<br>";our customer service is excellent
s excellent
Your c
customer service(3)join()字符串的链接
3.字符串的查找
(1)string strstr ( string haystack, string needle ) 别名:strchr,stristr和strstr类似不同在于不区分大小写
strrchr()相反的,查找的是最后一次出现的字符串
第一次出现起的字符串
<"<br>"; echo $domain2;er@example.com
e.com(2)查找位置
int strpos(string str,string needle,[int offset]) 没有找到返回的是false
返回从offset开始在str中查找needle的位置
$eg:$t-'hello world';
echo strpos($t,'o',5);
//7 从第o开始,查找o这个变量的位置,结果为7
int strrpos()
5.替换
str_replace("%body%","blank","<body text='%body%'")
6 。大写小问题
Strpos
查找字符串中第一次出现的字符串的位置Strrpos
查找字符串中某字符,继第一次之后的最先出现的位置。strpos(stripos无大小写)
strrpos(strripos无大小写)strstr
stristr(无大小写)str_replace
str_ireplace(无大小写)上一篇:php实现mysql数据库备份类
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