PHP count_chars() 函数

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实例

返回一个字符串，包含所有在 "Hello World!" 中使用过的不同字符（模式 3）：

<?php
$str = "Hello World!";
echo count_chars($str,3);
?>

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定义和用法

count_chars() 函数返回字符串中所用字符的信息（例如，ASCII 字符在字符串中出现的次数，或者某个字符是否已经在字符串中使用过）。

语法

count_chars(string,mode)
参数 描述
string 必需。规定要检查的字符串。
mode

可选。规定返回模式。默认是 0。以下是不同的返回模式：

  • 0 - Array, ASCII values as key names, occurrences as key values
  • 1 - Array, ASCII values as key names, occurrences as key values, only list values with occurrences greater than 0
  • 2 - Array, ASCII values as key names, occurrences as key values, only list values with occurrences equal to 0
  • 3 - String, with all used different characters
  • 4 - String, with all unused different characters

Technical Details

Return value: depending on the specified mode Parameters.
PHP Version: 4+

More Examples

Example 1

Returns a string containing all unused characters in "Hello World!" (pattern 4):

<?php
$str = "Hello World!";
echo count_chars($str,4);
?>

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Example 2

In this example, we will use count_chars() to check the string, with the return pattern set to 1. Pattern 1 will return an array, with ASCII values as key names and the number of occurrences as key values:

<?php
$str = "Hello World!";
print_r(count_chars($str,1));
?>

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Example 3

Another example of counting the number of occurrences of an ASCII character in a string:

<?php
$str = "PHP is pretty fun!!";
$strArray = count_chars($str,1);
foreach ($strArray as $key=>$value)
  {
echo "Character <b>'".chr($key)."'</b> found $value times.<br>";
  }
?>

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PHP String فونکشن