ctype函数_PHP ctype_cntrl（）函数与示例

ctype函数

PHP ctype_cntrl()函数 (PHP ctype_cntrl() function)

ctype_cntrl() function is a character type (CType) function in PHP, it is used to check whether a given string contains all control characters or not.

ctype_cntrl()函数是PHP中的字符类型(CType)函数，用于检查给定的字符串是否包含所有控制字符。

It returns true if all characters of the given strings are control characters (like, a newline character, tab character, escape character etc). Else it returns false.

如果给定字符串的所有字符都是控制字符(例如，换行符，制表符，转义符等)，则返回true 。否则返回false 。

Note: Though control characters are unprintable character i.e. they cannot be represented in the string format if we represent they may display like symbols. So, we can provide the escape sequences in the string by following with forwarding slash (\), we can also provide the control character’s ASCII code in the range of hexadecimal values from 0x00 to 0x1f and 0x7f (Del).

注意：尽管控制字符是不可打印的字符，即如果我们表示它们可能显示为类似符号，则它们不能以字符串格式表示。因此，我们可以在字符串后加上正斜杠( \ )来提供转义序列，还可以提供控制字符的ASCII代码，范围为从0x00到0x1f和0x7f (Del)的十六进制值。

To assign characters to value ASCII format (hexadecimal value), we use \x with the value.

要将字符分配给值ASCII格式(十六进制值)，我们使用\ x作为值。

Syntax:

句法：

    ctype_cntrl(string) : bool

Example:

例：

    Input: "\r\n"
Output: true
Input: "\t\x12"
Output: true
Input: "\x00\x12\x1f\x7f"
Output: true
Input: "Hello123"
Output: false

PHP code:

PHP代码：

<?php
$str1 = "\r\n";
if(ctype_cntrl($str1))
echo ("str1 contains all control characters.\n");
else
echo ("str1 does not contain all control characters.\n");
$str2 = "\t\x12";
if(ctype_cntrl($str2))
echo ("str2 contains all control characters.\n");
else
echo ("str2 does not contain all control characters.\n");
$str3 = "\x00\x12\x1f\x7f";
if(ctype_cntrl($str3))
echo ("str3 contains all control characters.\n");
else
echo ("str3 does not contain all control characters.\n");        
$str4 = "\r \n"; //space is there 
if(ctype_cntrl($str4))
echo ("str4 contains all control characters.\n");
else
echo ("str4 does not contain all control characters.\n");
$str5 = "Hello123"; //alphabets & digits are there
if(ctype_cntrl($str5))
echo ("str5 contains all control characters.\n");
else
echo ("str5 does not contain all control characters.\n");                
?>

Output

输出量

str1 contains all control characters.
str2 contains all control characters.
str3 contains all control characters.
str4 does not contain all control characters.
str5 does not contain all control characters.