XVII. Character Type Functions
簡介
The functions provided by this extension check whether a character or string falls into a certain character class according to the current locale (see also setlocale()).
When called with an integer argument these functions behave exactly like their C counterparts from ctype.h. It means that if you pass an integer smaller than 256 it will use the ASCII value of it to see if it fits in the specified range (digits are in 0x30-0x39). If the number is between -128 (inclusive) and 0 then 256 will be added and the check will be done on that.
When called with a string argument they will check every character in the string and will only return TRUE if every character in the string matches the requested criteria. When called with an empty string the result will always be TRUE.
Passing anything else but a string or integer will return FALSE immediately.
It should be noted that ctype functions are always preferred over regular expressions, and even to some equivalent str_* and is_* functions. This is because of the fact that ctype uses a native C library and thus processes significantly faster.
需求
None besides functions from the standard C library which are always available.
安裝
Beginning with PHP 4.2.0 these functions are enabled by default. For older versions you have to configure and compile PHP with --enable-ctype. You can disable ctype support with --disable-ctype.
PHP 的 Windows 版本已經內建該增加模組的支援。無需加載任何附加增加庫即可使用這些函數。
注: Builtin support for ctype is available with PHP 4.3.0.
運行時配置
本增加模組在 php.ini 中未定義任何配置選項。
資源類型
本增加模組未定義任何資源類型。
預定義常量
本增加模組未定義任何常量。
- 目錄
- ctype_alnum -- Check for alphanumeric character(s)
- ctype_alpha -- Check for alphabetic character(s)
- ctype_cntrl -- Check for control character(s)
- ctype_digit -- Check for numeric character(s)
- ctype_graph -- Check for any printable character(s) except space
- ctype_lower -- Check for lowercase character(s)
- ctype_print -- Check for printable character(s)
- ctype_punct -- Check for any printable character which is not whitespace or an alphanumeric character
- ctype_space -- Check for whitespace character(s)
- ctype_upper -- Check for uppercase character(s)
- ctype_xdigit -- Check for character(s) representing a hexadecimal digit