This article brings you a summary of commonly used functions in PHP strings (with examples). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
Commonly used functions in PHP:
| Function name | Description | Instance | |
|---|---|---|---|
| trim() | Remove spaces or other predefined characters at both ends of the string | "$str = "\r\nHello World!\r\n"; echo trim($str); | |
| #rtrim() | Remove spaces or other predefined characters on the right side of the string | "$str = "Hello World!\n\n"; echo rtrim ($str);" | |
| chop() | alias for rtrim() | Same as above | |
| ltrim() | Remove spaces or other predefined characters on the left side of the string | "$str = "\r\nHello World!"; echo ltrim($str);" | |
| dirname() | Return to the directory part of the path (we put it in the string function) | echo dirname("c: /testweb/home.php"); | |
| Pall the string to the specified length | $str = "Hello World "; echo str_pad($str,20,"."); | ||
| Reuse the specified string | echo str_repeat( ".",13); | ||
| Split the string into an array | print_r(str_split("Hello")) ; | ||
| Reverse the string | echo strrev("Hello World!"); | ||
| Wrap the string according to the specified length | "$str = ""An example on a long word is: Supercalifragulistic""; echo wordwrap( $str,15);" | ||
| Randomly shuffle all the characters in the string | echo str_shuffle("Hello World" ); | ||
| Parse the string into a variable | "parse_str("id=23&name=John Adams",$myArray) ; print_r($myArray);" | ##number_format() | |
| "echo number_format("1000000" ); echo number_format("1000000",2); echo number_format("1000000",2,"","",""."");" | ##strtolower() | ||
| echo strtolower("Hello WORLD!"); | ##strtoupper() | String Convert to uppercase | |
| ucfirst() | Capitalize the first letter of the string | ||
| ucwords() | Convert the first character of each word in the string to uppercase | ||
| htmlentities() | Convert characters to HTML entities | ||
| ##htmlspecialchars() | Convert predefined characters to html encoding | ||
| nl2br() | \nEscaped to | 标签echo nl2br("One line.\nAnother line."); | |
| strip_tags() | 剥去 HTML、XML 以及 PHP 的标签 | echo strip_tags("Hello world!"); | |
| addcslashes() | Add a backslash before the specified character to escape the characters in the string | $str = "" Hello, my name is John Adams." echo $str; echo addcslashes($str,'m');" | |
| stripcslashes() | Deleted by addcslashes( )Added backslash | echo stripcslashes("Hello, \my na\me is Kai Ji\m."); | |
| addslashes() | Add backslashes before specifying predefined characters | $str = "Who's John Adams?";echo addslashes($str); | |
| stripslashes() | Remove escape characters added by addslashes() | echo stripslashes("Who\'s John Adams?"); | |
| quotemeta( ) | Add a backslash before some predefined characters in the string | $str = "Hello world. (can you hear me?)"; echo quotemeta($str) ; | |
| chr() | Returns characters from the specified ASCII value | echo chr(052); | |
| ord() | Returns the ASCII value of the first character of the string | echo ord("hello"); | |
| Compare two strings without case sensitivity | echo strcasecmp("Hello world!","HELLO WORLD!"); | ||
| Compare two strings case-sensitively | |||
| Compare the first n characters of the string, Case sensitive | |||
| Compares the first n characters of the string, not case sensitive | int strncasecmp (string $str1, string $str2, int $len) | ##strnatcmp() | |
| int strnatcmp (string $str1, string $str2) | ##strnatcasecmp() | ||
| int strnatcasecmp ( string $str1 , string $str2 ) | chunk_split() | ||
| str chunk_split(str $ body[,int $len[,str $end]]) | strtok() | ||
| str strtok(str $ str,str $token) | explode() | ||
| array explode(str $sep ,str $str[,int $limit]) | ##implode() | Same as join, concatenate the array values into a string using predetermined characters | |
| substr() | Intercept string | ||
| ##str_replace() | String replacement operation, case sensitive | ||
| str_ireplace() | String replacement operation, case-insensitive | ||
| ##substr_count() | Count a string , the number of occurrences in another string | int substr_count ( string $haystack , string $needle [, int $offset = 0 [, int $length ]] ) | |
| substr_replace() | Replace a certain string in the string with another string | mixed substr_replace ( mixed $string , string $replacement , int $start [, int $length ] ) | |
| similar_text() | Returns the number of identical characters in the two strings | int similar_text(str $str1,str $str2) | |
| strchr() | Returns a string from the beginning to the end of another string | string strstr (string $str, string $needle, bool $before_needle ) | |
| strrchr() | Returns a string starting from the last occurrence of a string in another string to the end | string strrchr (string $haystack, mixed $needle) | |
| stristr() | Returns a string from the beginning to the end of another string , not case sensitive | string stristr ( string $haystack , mixed $needle [, bool $before_needle = false ] ) | |
| strtr() | Convert some characters in the string | string strtr (string $str, string $from, string $to) | |
| strpos() | Find the position where a certain character first appears in the string | int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] ) | |
| stripos () | Find the first occurrence of a character in a string, case-insensitive | int stripos ( string $haystack , string $needle [, int $offset ] ) | |
| strrpos() | Find the last occurrence of a character in a string | int strrpos ( string $haystack , string $needle [, int $offset = 0 ] ) | |
| strripos() | Find the last occurrence of a character in a string, case-insensitive | int strripos ( string $haystack , string $needle [, int $offset ] ) | |
| strspn() | Returns the length of the first substring in the string that matches the mask | int strspn ( string $str1 , string $str2 [, int $start [, int $length ]] ) | |
| strcspn() | Returns the length of the string that does not match the mask | int strcspn (string $str1, string $str2 [, int $start [, int $length ]] ) | |
| str_word_count() | Count the number of words contained in a string | mix str_word_count(str $str,[]) | |
| strlen() | Statistics string length | int strlen(str $str) | |
| count_chars() | Counts the number of occurrences of all letters in the string (0..255) | mixed count_chars ( string $string [, int $mode ] ) | |
| md5() | String md5 encoding | $str = "Hello"; echo md5($str) | |
| iconv | |||
| mb_substr | Get the part of the string | string mb_substr (string $str, int $ start [, int $length = NULL [, string $encoding = mb_internal_encoding() ]] ) | |
| mb_http_output | Set/get HTTP output character encoding | mixed mb_http_output ([ string $encoding = mb_http_output() ] ) | |
| mb_strlen | Get the length of the string | mixed mb_strlen ( string $ str [, string $encoding = mb_internal_encoding() ] ) | |
| iconv | The string is converted according to the required character encoding | string iconv ( string $in_charset , string $out_charset , string $str ) | |
| Intercept part of the string | |||
| Get iconv extended internal configuration variables | |||
| Count the number of occurrences of a string | |||
| Check whether the string is valid in the specified encoding | |||
| Find the last occurrence of a string in a string | |||
| Split using regular expressions Multi-byte string | |||
| Interpret the URL into an array |
Chinese mainly uses two encoding formats: GBK and utf-8.
GBK and utf-8 are two different encoding committees’ standards for encoding Chinese characters.
They stipulate that GBK is double-byte, that is, one Chinese character occupies 2Bytes.
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