[Recommended] Summary of various PHP string functions

PHP string functions include the character location search function, the sub-character extraction function, the replacement string, the character length, the comparison character function, the array character, and the space. String functions in PHP are also easy to understand. Today, we have summarized nearly 12 PHP string functions for you, hoping to help you with your needs and add

PHP string functions include the character location search function, the sub-character extraction function, the replacement string, the character length, the comparison character function, the array character, and the space. String functions in PHP are also easy to understand. Today, we have summarized nearly 12 PHP string functions for you, hoping to help you with your needs and add

PHP string functions include the character location search function, the sub-character extraction function, the replacement string, the character length, the comparison character function, the array character, and the space.

String functions in PHP are also easy to understand. Today, we have summarized nearly 12 PHP string functions for you, hoping to help other users and increase their PHP knowledge base.

1. character location search function:

Strpos ($ str, search, [int]): searches for the first position of search in $ str starting from int;

Stripos ($ str, search, [int]): the position where the string first appears in another string. This function is case insensitive.

Strrpos ($ str, search, [int]): searches for the last position of search in $ str starting from int.

Strripos ($ str, search, [int]): Same as above. This function is case insensitive.

2. Extract the sub-string function (dual-byte)

Substr ($ str, int start [, int length]): Extracts [length strings] starting from the strat position in $ str.

Strstr ($ str1, $ str2): searches for $ str2 from $ str1 (the first position) and truncates the string from the start to the end. If not, FALSE is returned.

Stristr () is the same as strstr, but is case insensitive.

Strrchr () is returned from the last searched character. Usage: get the file name in the path

3. PHP string functions that replace strings

Str_replace (search, replace, $ str): search for search from $ str and replace it with replace.

Str_ireplace (search, replace, $ str): Same as above. This function is case insensitive.

Strtr ($ str, search, replace): In this function, replace cannot be "";

Substr_replace ($ Str, $ rep, $ start [, length]): $ str original string, $ new string after rep replacement, $ start position, $ length replacement length, optional

4. Character Length

Int strlen ($ str)

5. Comparison of character Functions

Int strcmp ($ str1, $ str2): $ str1 >=< $ str2 is positive 1, 0,-1 (string comparison)

Strcasecmp () Same as above (case-insensitive)

Strnatcmp ("4", "14") compares strings in natural order

Strnatcasecmp () is the same as above (case sensitive)

6. PHP string functions split into Arrays

Str_split ($ str, len): splits $ str by len Length and returns an array.

Split (search, $ str [, int]): splits $ str by the search character and returns the number of times the array int is split.

Expload (search, $ str [, int])

7. Remove spaces:

Ltrim (), rtrim (), trim ()

8. Space Function

Chunk_split ($ str, 2): Add a space to the $ str string;

9. chr and ord -- return the specified character or ascii

10. functions related to HTML code

Nl2br (): converts \ n
.

Strip_tags ($ str [,'

']): Removes HTML and PHP tags.

In $ str, all HTML and PHP code will be removed. The optional parameters are html and PHP code.

Code written by optional parameters.

For example, echo strip_tags ($ text ,'

');

Htmlspecialchars ($ str [, parameter]): HTML code parameters are output normally on the page, which is a conversion method.

11. PHP string functions for case-insensitive character conversion

Strtolower ($ str): converts a string to lowercase.

Strtoupper ($ str): converts string to uppercase

Ucfirst ($ str): converts the first character of a function to uppercase.

Ucwords ($ str): converts the first letter of each word to uppercase.

12. Database-related PHP string functions

Addslashes ($ str): enables single quotation marks ('), double quotation marks ("), backslash (\), and NUL in str.

String \',\",\\.

Magic_quotes_gpc = On: automatically escapes get, post, and cookie content.

Get_magic_quotes_gpc (): checks whether magic_quotes_gpc is enabled.

Stripslashes (): removes the backslash from the string.