PHP Find String Learning Note _php Tutorial

This article describes some methods of finding strings in PHP, including: Finding a string, finding the number of occurrences of a string, finding a string position, three ways to find a string, and a friend you need to know to access the reference.

PHP string Lookup characters can be implemented through the STRSTR (), STRRCHR () functions, and the two functions are structured as follows:

Strstr ($haystack, $needle)
STRRCHR ($haystack, $needle)

$haystack represents a female string, $needle represents the character to find
The Strstr () function is used to find the position of the first occurrence of a character and returns the part from which the position begins to the end of the parent string;

The STRRCHR () function is used to find the position of the last occurrence of a character, and returns the portion from this position to the end of the parent string.

Instance:

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$a = "P"; $b = "echo is PHP function, p is HTML tag"; $str 1=strstr ($b, $a); if ($str 1) echo $str 1. " "; else echo "Could not find P". " "; $str 2=STRRCHR ($b, $a); if ($str 2) echo $str 2; else echo "Cannot find P"; ?>

PHP string occurrences can be found through the Substr_count () function, the structure of the form:

Substr_count ($haystack, $needle [, $offset [, $length]])
$haystack represents a female string, $needl represents the character to find
$offset represents the starting point for the lookup, $length the length of the lookup, which is an optional parameter
Instance:

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$str = "This is a test"; Echo Substr_count ($str, ' is '). ' '; Echo Substr_count ($str, ' is ', 3). ' '; Echo Substr_count ($str, ' is ', 3, 3). ' '; ?>

PHP Lookup string Locations can be implemented using the Strrpos (), Strpos () function.

Find the last Location
Using 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 supplied, only the first character in the string is taken, and the other characters are invalid;
Optional parameter $offset sets the length of the lookup string.
Example 1:

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$text = "PHP"; $str 1=strrpos ($text, "P"); if ($str 1) echo "found the character ' P '". "; else echo "Cannot find the character ' P '". "; $str 2=strrpos ($stxt, "Q"); if ($str 2) echo "found the character ' Q '". "; else echo "Cannot find the character ' Q '". "; ?>

Find the location for the first time
With the Strpos () function, and the function Strrpo () Only one letter, the function is very different. The $needle parameter of the Strpos () function allows the use of a string, and finds the first occurrence of the string in $haystack, rather than the last time.

Instance:

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$text = "One of the differences between the PHP language and the ASP language: PHP is more stable and secure"; $str 1=strrpos ($text, "PHP"); if ($str 1) echo "found the string ' php ', the location is now: $str 1". " "; else echo "Could not find the string ' php '". "; $str 2=strpos ($stxt, "PHP"); if ($str 2) echo "found the string ' php '". "; else echo "Could not find the string ' php '". "; ?>

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