PHP String function classification, phpstring function_PHP tutorial

PHP String function classification, phpstring function

1. Find character position function:

strpos ($str,search,[int]): Find the first position of search in $str starting from int;

stripos ($str,search,[int]): The function returns the position of the first occurrence of a string in another string. This function is not case sensitive

strrpos ($str,search,[int]): Find the last occurrence of search in $str starting from int

2. Extract sub-character function (double bytes)

submit ($str,int start[,int length]): Extract [length-length string] starting from the strat position in $str.

strstr ($str1,$str2): Search $str2 from $str1 (the first position) and intercept the string starting from it to the end; if not, return FALSE.

stristr() has the same function as strstr, except that it is not case-sensitive.

strrchr() returns from the last character searched; use: to get the file name in the path

3. Replace string

str_replace (search,replace,$str): Find search from $str and replace

str_irreplace (search,replace,$str): Not case sensitive

strtr ($str,search,replace): replace in this function cannot be "";

substr_replace ($str,$rep,$start[,length]) $str original string, $rep new string after replacement, $start starting position, $length replacement length, this item Optional

4. Character length

int strlen($str)

5. Comparison character function

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

strcasecmp() Same as above (not case sensitive)

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

strnatcasecmp() Same as above, (case sensitive)

6. Split into array functions

str_split ($str,len): Split $str according to the length of len and return the array

split (search,$str[,int]): Split $str according to the search character and return the array int how many times it is divided, and the rest will not be divided

explode (search,$str[,int])

7. Remove spaces: ltrim, rtrim, trim

8. Add space function

chunk_split ($str,2); Press 2 characters into the $str character to add a space;

9, chr, ord -- return the specified character or ascii

10. Functions related to HTML code

nl2br(): Convert n to
.

strip_tags($str[,'

']): Remove HTML and PHP tags. All HTML and PHP code in $str will be removed, and the optional parameters are html and PHP codes that will retain the code written by the optional parameters. For example: echo strip_tags($text, '

');

htmlspecialchars($str[, parameter]): The normal output of the page HTML code parameters is the conversion method

11. Character case conversion function

strtolower($str) converts the string to lowercase

strtoupper($str) Convert string to uppercase

ucfirst($str) Converts the first character of the function to uppercase

ucwords($str) Converts the first letter of each word to uppercase

12. Database related functions

Addslashes($str): Convert single quotes ('), double quotes ("), backslashes () and NUL strings in str to ',",\.

Magic_quotes_gpc = On Automatically escape the content of get post cookie

Get_magic_quotes_gpc() Check whether magic_quotes_gpc is turned on

When magic_quotes_gpc=On, the function get_magic_quotes_gpc() will return 1

When magic_quotes_gpc=Off, the function get_magic_quotes_gpc() will return 0

Stripslashes() removes backslashes from strings