1.strcmp($str1, $str2) If equal, return 0, $str1>$str2 returns 1, $str1
2.strncmp($str1,$str2, $length) intercepts the strings of $str1 and $str2 starting from 0 and has a length of $length for comparison. The output result is the same as the first example.
3.strstr($str, $need, bool $return_before=false) Important string search function This function is equivalent to strchr(), the string operated by $str, the character to be found in $need String, $return_before returns the string with $need before $str. The return value of this function is the first occurrence position of $need string in $str to the last position of $str.
4.strrchr($str, $need) From the last occurrence of $need in string $str to the end of $str
5.$strpos($str,$ need) The position where $need appears for the first time in $str. If the position of $str is not found, null is returned. It is not case sensitive. stripos()
6.strrpos($str,$need)The last time in $str If $need appears, null is returned if not found. If it is not case-sensitive, you can use strripos()
7.strpbrk($str,$charlist) $str is the string to be operated on, $charlist character set ( $charlist = 'abcde'), Search for any character in $charlist in $str, and return the remaining part starting from the first occurrence of the specified character
8.substr($ str,$start,$length) Important String interception function, intercepts the string with a length of $length starting from the $start position in $str
9.explode($delimiter,$ str, $limit=null) string splitting function, $delimiter is the delimiter, $str is the operator, the delimiter cannot be empty, it returns false if it is empty, and returns an array by default.
10.implode($ glue, array $pieces) The important String connection function connects each element of $pieces in the array according to the connector $gule to generate a new string return, which is equivalent to the join() function.
11.str_split($str, $length) splits $str according to the length specified by $length and returns the array. Note that mb_split() is more compatible with Chinese.
12.str_replace($search,$replace,$str) important string replacement function, $search in $str is replaced with $replace.
13.substr_replace ($str,$replacement,$start,$length=null) substring replacement function, the substring of $length starting from $start in $str is replaced with $replacement.
14. str_repeat($str,$times) repeats $str $times times to generate a new string and returns
15.str_pad($str,$pad_length,$pad_str,$pad_type) string filling function, $ The string that str is operated on, $pad_length is the length to be filled, $pad_str is the string used for filling, $pad_type:STR_PAD_LEFT, etc. indicates the position of the filling string.
16.ord(string $char) Return the code value corresponding to ASCII chr (int $ascii) Returns the string corresponding to the ASCII code value
17.strrev($str) String reversal
18.strip_tags($str,$remain_tags), delete html or xml tags as long as will be filtered out, you can set the tags that need to be retained in $remain_tags
19.nl2br($str) in the new Add line break
before the line. Supplement: mb (multibyte) Chinese or other text characters are composed of multiple bytes. Previous string splitting and other functions that did not start with mb all started with a Operations are performed in units of bytes, which will bring unexpected operation results for Chinese characters, so mbstring provides a good operation method.
The above is the detailed content of Summary of php string built-in functions. For more information, please follow other related articles on the PHP Chinese website!

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mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),