strstr
The strstr() function searches for the first occurrence of one string within another string.
This function returns the rest of the string (from the matching point). Returns false if the searched string is not found.
The code is as follows:
<?php
$email = 'user@example.com';
$domain = strstr($email, '@');
echo $domain;
// prints @example.com
?>stristr
The stristr() function finds the first occurrence of a string within another string.
If successful, the remainder of the string (from the point of the match) is returned. If the string is not found, returns false.
It is used exactly the same as strstr. The only difference is that strstr is not case sensitive.
strpos
The strpos function returns a boolean value. Needless to say, FALSE and TRUE. Use "===" to make a judgment. The execution speed of strpos is faster than the above two functions. In addition, strpos has a parameter to specify the judgment position, but the default is empty. It means to judge the entire string. The disadvantage is that it does not support Chinese well.
Example 1
if(strpos('www.jb51.net','jb51') !== false){
echo '包含jb51';
}else{
echo '不包含jb51';
}Example 2
$str= 'abc';
$needle= 'a';
$pos = strpos($str, $needle); // 返回第一次找到改字符串的位置，这里返回为1，若查不到则返回Falseexplode
Use explode to judge. The PHP judgment string contains the following code:
function checkstr($str){
$needle ='a';//判断是否包含a这个字符
$tmparray = explode($needle,$str);
if(count($tmparray)>1){
return true;
} else{
return false;
}
}substr
For example, we need to determine whether the last character is a specified character
<?php
/*
$str1="<p>这是个winrar专用的dll然后下哦啊不错的dll文件，QlogWin32.dll</p>";
if(substr($str1,-8)==".dll</p>"){
echo substr($str1,0,-4);
}substr_count
Count the number of times "substring" appears in "original string"
The substr_count() function is the number of times a small string appears in a large string:
$number = substr_count(big_string, small_string);
Just today I need a function to find a string. To determine whether the string big_string contains the string small_string, return true or fasle;
After checking the manual for a long time, I couldn't find a ready-made function, so I thought that I could use the substr_count function to implement the code as follows:
function check_str($str, $substr)
{
$nums=substr_count($str,$substr);
if ($nums>=1)
{
return true;
}
else
{
return false;
}
}Super easy!
For specific details, you can look up related functions for advanced applications.
