PHP chr()函数用法介绍

chr()function是PHP中的内置函数, 用于将ASCII值转换为字符。它接受ASCII值作为参数, 并返回表示来自指定ASCII值的字符的字符串。 ASCII值可以十进制, 八进制或十六进制值指定。

• 八进制值由前导0定义。
• 十六进制值由前导0x定义。

的ASCII码值表可以参考这里。

语法:

string chr( $asciiVal)

参数：此函数接受单个参数$ asciiVal。此参数包含有效的ASCII值。 chr()函数返回我们传递给它的ASCII值的相应字符作为参数$ asciiVal。

返回值：该函数返回我们传递其ASCII值的字符。

例子：

Input :  ASCII=35 ASCII=043 ASCII=0x23
Output : # # # 
Explanation: The decimal, octal and hex value of '#' is 
35, 043 and 0x23 respectively

Input : ASCII=48 
Output : 0

下面的程序说明了PHP中的chr()函数：

程序1：传递不同的ASCII但等效字符相同时, 演示chr()函数的程序。

<?php
// PHP program to demonstrate the chr() function
  
$n1 = 35;
$n2 = 043;
$n3 = 0x23;
  
echo "The equivalent character for ASCII 35 in decimal is " ;
echo chr ( $n1 ), "\n" ; // Decimal value
  
echo "The equivalent character for ASCII 043 in octal is " ;
echo chr ( $n2 ), "\n" ; // Octal value
  
echo "The equivalent character for ASCII 0x23 in hex is " ;
echo chr ( $n3 ); // Hex value
  
?>

输出如下：

The equivalent character for ASCII 35 in decimal is #
The equivalent character for ASCII 043 in octal is #
The equivalent character for ASCII 0x23 in hex is #

程式2：程序演示使用数组的chr()函数。

<?php
// PHP program to demonstrate the chr() function
// in array 
  
$a =[48, 49, 50]; 
foreach ( $a as $i )
{
     echo "The character equivalent of 
                  ASCII value of ", $i, " is ";
     echo chr ( $i ), "\n" ;
}
  
?>

输出如下：

The character equivalent of ASCII value of 48 is 0
The character equivalent of ASCII value of 49 is 1
The character equivalent of ASCII value of 50 is 2

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