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HomeBackend DevelopmentPHP Tutorial如何使用PHP中的字符串函数_PHP

PHP中的字符串操作功能是比较多的,重要的有以下这些:  

(1)echo,print,printf,sprintf 
前两个函数是输出字符串.字符串中如果有变量名则被替换成其值.  
后两个函数类似于C的同名函数. 

(2)strchr,strlen,strtok,strrchr,strrev,strstr,strtolower, 
strtoupper,substr,ucfirst 
这些是常用的字符串操作函数,有些和C中的同名函数意义完全一致.  
strrev是把一个字符串翻转. 
strtolower和strtoupper的意思应该不用解释了. 
ucfirst是把字符串的第一个字符变成大写. 
substr是返回字符串的一个子串,用法是:substr(字符串,头,长度).
头位置是  从0算起的.如果是负数,则是从尾部向前数的意思. 

(3)Chr,Ord 
类似于C的同名函数. 

(4)explode,implode,join 
这些是和数组有关的函数. 
explode(字符串,分割符)返回一个将字符串在分割符处分开所产生的数组. 
implode(数组,分割符)返回一个将数组各元素之间插上分割符而成的字符串. 
join与implode意义相同. 

(5)Chop 
去掉字符串尾部的空白. 

(6)htmlspecialchars 
将字符串中的HTML特殊字符换成它们的名字,例如\"

(7)nl2br 
在字符串中的每一个回车前面加上\"
\". 

(8)AddSlashes,StripSlashes 
分别给字符串中需要加上\"\\"才能用于数据库查询的字符加上和去掉\"\\".  

(9)parse_str 
将\"name1=value1&name2=value2&...\"类型的字符串分析成一些变量.  
例如: 
   parse_str(\"a=1&b=2\"); 
生成$a与$b两个变量,值分别为1,2. 
如果有两对名字/值的名字部分相同,则后一个的值覆盖前一个的.  
如果这两对的名字尾部都有\"[]\",例如\"a[]=1&a[]=2\",则生成数组$a,两个元素分别为1,2

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