Query that the php string contains specified data

This time I will bring you a queryphp stringcontains the specified data, what are the notesif the query php string contains the specified data, the following is a practical case, one Get up and take a look.

When writing a program, you often have to process strings. The most basic thing is to search for strings. You can use regular rules to detect whether a string contains a specified string in PHP. If you don’t understand regular rules, there are a few function for your convenience.

1. strstr

strstr() function searches for the first occurrence of a string in 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
 /*如手册上的举例*/
 $email = &#39;user@example.com&#39;;
 $domain = strstr($email, &#39;@&#39;);
 echo $domain;
 // prints @example.com
?>

2. stristr

stristr() function finds the first occurrence of a string in another string .
If successful, return the remainder of the string (from the point of the match). 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.

3. strpos

The strpos function returns boolean Needless to say value. FALSE and TRUE. Use "===" to judge. strpos is faster than the above two functions in terms of execution speed. 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False

4. explode

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;
 }
}

5. substr. For example, we need to judge 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);
}

6, substr_count Count the number of times "substring" appears in the "original string"

substr_count() function is a small string in a large string The number of occurrences in:
$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 any 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 simple!

For specific details, you can look up related functions for advanced applications.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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