https://www.w3schools.com/pHp/func_string_substr_compare.asp
PHP substr_compare() Function
Well organized and easy to understand Web building tutorials with lots of examples of how to use HTML, CSS, JavaScript, SQL, Python, PHP, Bootstrap, Java, XML...
php substrcomparefunction
https://www.php.net/manual/de/function.substr-count.php
PHP: substr_count - Manual
Ermittelt, wie oft eine Zeichenkette in einem String vorkommt
php substrcountmanual
https://www.naukri.com/code360/library/php-substr-function
PHP substr() Function - Naukri Code 360
In this article, we will cover the syntax, parameters, and return type of the substr() function, along with examples to help you understand its usage better.
php substrfunctionnaukricode360
https://www.php.net/manual/zh/function.substr-replace.php
PHP: substr_replace - Manual
php substrreplacemanual
https://www.openwall.com/lists/oss-security/2011/03/13/9
oss-security - Re: CVE request: PHP substr_replace() use-after-free
php substrosssecuritycverequest
https://www.php.net/manual/uk/function.mb-substr.php
PHP: mb_substr - Manual
phpmbsubstrmanual
https://www.php.net/manual/it/function.grapheme-substr.php
PHP: grapheme_substr - Manual
Return part of a string
phpgraphemesubstrmanual
https://www.php.net/manual/it/function.mb-substr-count.php
PHP: mb_substr_count - Manual
Count the number of substring occurrences
phpmbsubstrcountmanual
https://www.php.net/manual/en/function.grapheme-substr.php
PHP: grapheme_substr - Manual
Return part of a string
phpgraphemesubstrmanual
https://www.php.net/manual/uk/swoole-buffer.substr.php
PHP: Swoole\Buffer::substr - Manual
Read data from the memory buffer based on offset and length. Or remove data from the memory buffer.
phpswoolebuffersubstrmanual
https://www.php.net/mb_substr
PHP: mb_substr - Manual
phpmbsubstrmanual
https://www.php.net/manual/uk/eventbuffer.substr.php
PHP: EventBuffer::substr - Manual
Substracts a portion of the buffer data
phpeventbuffersubstrmanual