PHP search string study notes_PHP tutorial

This article introduces some methods of finding strings in php, including three operations on string search: finding strings, finding the number of occurrences of a string, and finding the position of a string. Friends who need to know more can go to the reference refer to.

PHP string search characters can be realized through the strstr() and strrchr() functions. The structure of the two functions is as follows:

strstr($haystack, $needle)
strrchr($haystack, $needle)

//$haystack represents the parent string, $needle represents the character to be found
The strstr() function is used to find the position of the first occurrence of a character and return the part starting from this position to the end of the parent string;

The

strrchr() function is used to find the position of the last occurrence of a character and return the part starting from this position to the end of the parent string.

Example:

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代码如下	复制代码
$a="p";  $b="echo是php函数,p是html标记";  $str1=strstr($b,$a);  if($str1)   echo $str1 ." ";  else echo "找不到p" ." ";    $str2=strrchr($b,$a);   if($str2)   echo $str2;  else echo "找不到p";  ?>

$a="p";

$b="echo is a php function, p is an html tag";

$str1=strstr($b,$a);

if($str1)
echo $str1 ."
";
else echo "p not found" ."
";

$str2=strrchr($b,$a);

代码如下	复制代码
$str="this is a test";  echo substr_count($str,'is') .' ';  echo substr_count($str,'is',3) .' ';  echo substr_count($str,'is',3,3) .' '; ?>

if($str2)

echo $str2;

else echo "p not found";

?>
The search for the number of occurrences of a PHP string can be achieved through the substr_count() function, whose structural form is:

substr_count($haystack, $needle [,$offset [,$length]])
//$haystack represents the parent string, $needl represents the character to be found
//$offset represents the starting point of the search, $length represents the length of the search, both are optional parameters
Example:

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代码如下	复制代码
$text="php";  $str1=strrpos($text,"p");  if($str1)   echo "找到字符'p'" ." ";  else echo "找不到字符'p'" ." ";  $str2=strrpos($stxt,"q");   if($str2)   echo "找到字符'q'" ." ";  else echo "找不到字符'q'" ." "; ?>

$str="this is a test"; echo substr_count($str,'is') .'
'; echo substr_count($str,'is',3) .'
'; echo substr_count($str,'is',3,3) .'
'; ?>

PHP can find the string position through strrpos() and strpos() functions. Find the last location Use the function strrpos(), the structure is as follows: strrpos($haystack ,$needle [,$offset]) //The parameter $needle can only be one character, not a string. If a string is provided, only the first character in the string will be taken, and other characters will be invalid; //The optional parameter $offset sets the length of the search string. Example 1:

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$text="php"; $str1=strrpos($text,"p"); if($str1) echo "Character 'p' found" ." "; else echo "Character 'p' not found" ." "; $str2=strrpos($stxt,"q"); if($str2) echo "Character 'q' found" ." "; else echo "Character 'q' not found" ." "; ?>

Find the first location
Use the strpos() function, which is only one letter different from the function strrpo(), but the functions are very different. The $needle parameter of the strpos() function allows the use of strings and searches for the first occurrence of this string in $haystack, rather than the last occurrence.

Example:

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代码如下	复制代码
$text="php语言和asp语言的区别之一:php更加稳定安全";  $str1=strrpos($text,"php");  if($str1)   echo "找到字符串'php'，位置出现在:$str1" ." ";  else echo "找不到字符串'php'" ." ";  $str2=strpos($stxt,"php");   if($str2)   echo "找到字符串'php'" ." ";  else echo "找不到字符串'php'" ." "; ?>

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$text="One of the differences between php language and asp language: php is more stable and secure";

$str1=strrpos($text,"php");

if($str1) echo "The string 'php' was found, the position appears at: $str1" ."
"; else echo "String 'php' not found" ."
"; $str2=strpos($stxt,"php"); if($str2) echo "String 'php' found" ."
"; else echo "String 'php' not found" ."
"; ?>

http://www.bkjia.com/PHPjc/628834.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/628834.htmlTechArticleThis article introduces some methods of finding strings in php, including: finding strings, finding string occurrences There are three operations on string search: times and search string position. If necessary...