Easy to confuse four PHP text functions strstr strrchr substr stristr_php Tutorial

These four functions in PHP are often confusing, and here are some notes to take.

1, Strstr

strstr-displays the string that was found for the first time, to find, and subsequent strings. Case sensitive.

Code Listing:

[PHP]
strstr function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = Strstr ($email, ' @ ');
echo "strstr test result: {$domain}
";
$domain = Strstr ($email, ' @ ', true);
echo "strstr test result: {$domain}
";
/*
The test results are:
STRSTR test Result: @sina. com@qq.com
STRSTR test Result: liruxing1715
*/

strstr function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = Strstr ($email, ' @ ');
echo "strstr test result: {$domain}
";
$domain = Strstr ($email, ' @ ', true);
echo "strstr test result: {$domain}
";
/*
The test results are:
STRSTR test Result: @sina. com@qq.com
STRSTR test Result: liruxing1715
*/NOTE: Returns FALSE if the string you are looking for is not found.

2, Stristr

The stristr-function is the same as the STRSTR function, and the only difference is the sense of capitalization.

3, STRRCHR

The strrchr-displays the string that was last found, to find, and subsequent strings.

Code Listing:

[PHP]
STRRCHR function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = STRRCHR ($email, ' @ ');
echo "STRRCHR test result: {$domain}
";
/*
The test results are:
STRRCHR test Result: @qq. com
*/

STRRCHR function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = STRRCHR ($email, ' @ ');
echo "STRRCHR test result: {$domain}
";
/*
The test results are:
STRRCHR test Result: @qq. com
*/NOTE: Returns FALSE if the string you are looking for is not found.

4, substr

substr-in a string, the character is intercepted according to the given length.

Format: String substr (string $string, int $start [, int $length])

Parameter description:

$string: the string to intercept;

$start: The starting position to intercept is starting at 0, and if start is a negative number, the returned string starts at the end of the $string at the beginning of the first $start character, or FALSE if the length of the string is less than or equal to start.

$length: The end position of the intercept, if the first $length is empty, then return from the start position to the end.

Code Listing:

[PHP]
substr function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = substr ($email, 10);
echo "substr test result: {$domain}
";
$domain = substr ($email, 10, 5);
echo "substr test result: {$domain}
";
$domain = substr ($email,-5, 5); The last digit of the string is-1
echo "substr test result: {$domain}
";
/*
The test results are:
SUBSTR test Result: 15@sina.com@qq.com
SUBSTR test Result: 15@si
SUBSTR test Result: q.com
*/

substr function
$email = ' liruxing1715@sina.com@qq.com ';
$domain = substr ($email, 10);
echo "substr test result: {$domain}
";
$domain = substr ($email, 10, 5);
echo "substr test result: {$domain}
";
$domain = substr ($email,-5, 5); The last digit of the string is-1
echo "substr test result: {$domain}
";
/*
The test results are:
SUBSTR test Result: 15@sina.com@qq.com
SUBSTR test Result: 15@si
SUBSTR test Result: q.com
*/

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