count_chars

(PHP 4, PHP 5, PHP 7, PHP 8)

count_chars — 返回字符串中使用的字符信息

描述

count_chars(string $string, int $mode = 0): array|string

统计 string 中每个字节值（0..255）出现的次数，并以各种方式返回结果。

参数

string: 要检查的字符串。
mode: 参见返回值。

返回值

根据 mode，count_chars() 返回以下内容之一：

0 - 一个数组，字节值为键，每个字节的频率为值。
1 - 与 0 相同，但只列出频率大于零的字节值。
2 - 与 0 相同，但只列出频率等于零的字节值。
3 - 返回包含所有唯一字符的字符串。
4 - 返回包含所有未使用字符的字符串。

变更日志

版本	描述
8.0.0	在此版本之前，该函数在失败时返回 `false`。

示例

示例 #1 count_chars() 示例

<?php
$data = "Two Ts and one F.";

foreach (count_chars($data, 1) as $i => $val) {
 echo "There were $val instance(s) of \"" , chr($i) , "\" in the string.\n";
}
?>

上面的示例将输出

There were 4 instance(s) of " " in the string.
There were 1 instance(s) of "." in the string.
There were 1 instance(s) of "F" in the string.
There were 2 instance(s) of "T" in the string.
There were 1 instance(s) of "a" in the string.
There were 1 instance(s) of "d" in the string.
There were 1 instance(s) of "e" in the string.
There were 2 instance(s) of "n" in the string.
There were 2 instance(s) of "o" in the string.
There were 1 instance(s) of "s" in the string.
There were 1 instance(s) of "w" in the string.

参见

strpos() - 在字符串中查找子字符串首次出现的位置
substr_count() - 统计子字符串出现的次数

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＋添加注释

用户贡献的注释 11 条注释

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marcus33cz ¶

12 年前

如果您在使用多字节字符串时遇到 count_chars 问题，您可以更改页面编码。或者，您也可以使用此 mb_count_chars 版本的函数。基本上它是原始函数的“1”模式。

<?php
/**
 * 统计多字节字符串中的字符出现次数
 * @param string $input UTF-8 数据
 * @return array 字符的关联数组。
 */
function mb_count_chars($input) {
 $l = mb_strlen($input, 'UTF-8');
 $unique = array();
 for($i = 0; $i < $l; $i++) {
 $char = mb_substr($input, $i, 1, 'UTF-8');
 if(!array_key_exists($char, $unique))
 $unique[$char] = 0;
 $unique[$char]++;
 }
 return $unique;
}

$input = "Let's try some Greek letters: αααααΕεΙιΜμΨψ, Russian: ЙЙЫЫЩН, Czech: ěščřžýáíé";
print_r( mb_count_chars($input) ); 
//returns: Array ( [L] => 1 [e] => 7 [t] => 4 ['] => 1 [s] => 5 [ ] => 9 [r] => 3 [y] => 1 [o] => 1 [m] => 1 [G] => 1 [k] => 1 [l] => 1 [:] => 3 [α] => 5 [Ε] => 1 [ε] => 1 [Ι] => 1 [ι] => 1 [Μ] => 1 [μ] => 1 [Ψ] => 1 [ψ] => 1 [,] => 2 [R] => 1 [u] => 1 [i] => 1 [a] => 1 [n] => 1 [Й] => 2 [Ы] => 2 [Щ] => 1 [Н] => 1 [C] => 1 [z] => 1 [c] => 1 [h] => 1 [ě] => 1 [š] => 1 [č] => 1 [ř] => 1 [ž] => 1 [ý] => 1 [á] => 1 [í] => 1 [é] => 1 )
?>

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Eric Pecoraro ¶

19 年前

<?php

// 在字符串中需要 (n) 个唯一字符
// 对下面函数的修改，在给定字符串中需要多少个唯一字符方面增加了灵活性。

$pass = '123456' ; // true
$pass = '111222' ; // false

req_unique($pass,3);

function req_unique($string,$unique=3) {
 if ( count(count_chars($string,1)) < $unique) {
 echo 'false';
 }else{
 echo 'true';
 }
}

?>

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seb at synchrocide dot net ¶

20 年前

经过多次尝试和错误，试图创建一个函数来查找字符串中唯一字符的数量，我找到了 count_chars() - 我 20 多行无用的代码被它取代了。

<?
function unichar($string) {
$two= strtolower(str_replace(' ', '', $string));
$res = count(count_chars($two, 1));
return $res;
}

/* 例子 :: */

echo unichar("bob"); // 2
echo unichar("Invisibility"); //8
echo unichar("The quick brown fox slyly jumped over the lazy dog"); //26

?>

我不知道它可以在哪里使用，但它很有趣。

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匿名 ¶

8 年前

count_chars 支持多字节。

<?php

function mb_count_chars ($string, $mode = 0) {
 
 $result = array_fill(0, 256, 0);
 
 for ($i = 0, $size = mb_strlen($string); $i < $size; $i++) {
 $char = mb_substr($string, $i, 1);
 if (strlen($char) > 1) {
 continue;
 }
 
 $code = ord($char);
 if ($code >= 0 && $code <= 255) {
 $result[$code]++;
 }
 }
 
 switch ($mode) {
 case 1: // same as 0 but only byte-values with a frequency greater than zero are listed.
 foreach ($result as $key => $value) {
 if ($value == 0) {
 unset($result[$key]);
 }
 }
 break;
 case 2: // same as 0 but only byte-values with a frequency equal to zero are listed.
 foreach ($result as $key => $value) {
 if ($value > 0) {
 unset($result[$key]);
 }
 }
 break;
 case 3: // a string containing all unique characters is returned.
 $buildString = '';
 foreach ($result as $key => $value) {
 if ($value > 0) {
 $buildString .= chr($key);
 }
 }
 return $buildString;
 case 4: // a string containing all not used characters is returned.
 $buildString = '';
 foreach ($result as $key => $value) {
 if ($value == 0) {
 $buildString .= chr($key);
 }
 }
 return $buildString;
 }
 
 // change key names...
 foreach ($result as $key => $value) {
 $result[chr($key)] = $value;
 unset($result[$key]);
 }
 
 return $result;
 
}
?>

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-1

Andrey G ¶

4 years ago

检查两个字符串是否为变位词

<?php

function isAnagram($string1, $string2)
{
 return count_chars($string1, 1) === count_chars($string2, 1);
}

isAnagram('act', 'cat'); // true

?>

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-1

pzb at novell dot com ¶

17 years ago

此函数非常适合输入验证。我经常需要检查字符串中的所有字符是否为 7 位 ASCII（而不是空）。这是我迄今为止找到的最快函数

<?php
function is7bit($string) {
 // 空字符串是 7 位干净的
 if (!strlen($string)) {
 return true;
 }
 // count_chars 按升序八位字节顺序返回字符
 $str = count_chars($str, 3);
 // 检查空字符
 if (!ord($str[0])) {
 return false;
 }
 // 检查 8 位字符
 if (ord($str[strlen($str)-1]) & 128) {
 return false;
 }
 return true;
}
?>

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-3

phpC2007 ¶

16 years ago

这是一个用于统计字符串中字符串数量的函数。它可以用作简单的 utf8 启用 count_chars（但仅限于单一模式）...

<?php
function utf8_count_strings($stringChar)
{
 $num = -1;
 $lenStringChar = strlen($stringChar);
 
 for ($lastPosition = 0; 
 $lastPosition !== false;
 $lastPosition = strpos($textSnippet, $stringChar, $lastPosition + $lenStringChar))
 {
 $num++;
 }
 
 return $num;
}
?>

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-6

qeremy [atta] gmail [dotta] com ¶

11 years ago

另一种统计 Unicode 字符的方法。

<?php
function count_chars_unicode($str, $x = false) {
 $tmp = preg_split('//u', $str, -1, PREG_SPLIT_NO_EMPTY);
 foreach ($tmp as $c) {
 $chr[$c] = isset($chr[$c]) ? $chr[$c] + 1 : 1;
 }
 return is_bool($x)
 ? ($x ? $chr : count($chr))
 : $chr[$x];
}

$str = "şeker şeker yâriiiiiiiiiimmmmm";
print_r(count_chars_unicode($str, 'â')); // frequency of "â"
print_r(count_chars_unicode($str)); // count of uniq chars
print_r(count_chars_unicode($str, true)); // all chars with own frequency
?>

输出；
1
9
数组
(
[ş] => 2
[e] => 4
[k] => 2
[r] => 3
    [ ] => 2
[y] => 1
[â] => 1
[i] => 10
[m] => 5
)

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-5

mlong at mlong dot org ¶

22 years ago

// 这两个函数的用处


<?php 
 $string="aaabbc"; 
 
 // 只想统计字母 a 的数量 
 $acount=substr_count($string,"a"); 
 
 // 想同时统计字母 a 和字母 b 的数量 
 $counts=count_chars($string,0); 
 $acount=$counts[ord("a")]; 
 $bcount=$counts[ord("b")]; 
?>

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-7

maotin at hongkong dot com ¶

23 年前

以下是关于这个相对较新且非常实用的函数的一些更多实验。


<?php 
$string = 'I have never seen ANYTHING like that before! My number is "4670-9394".'; 
 
foreach(count_chars($string, 1) as $chr => $hit) 
echo 'The character '.chr(34).chr($chr).chr(34).' has appeared in this string '.$hit.' times.<BR>'; 
 
#The result looks like 
#The character " " has appeared in this string 11 times. 
 
echo count_chars($string,3); 
#The output is '!"-.034679AGHIMNTYabefhiklmnorstuvy' 
 
echo strlen($string).' is not the same as '.strlen(count_chars($string, 3)); 
 
#This shows that '70 is not the same as 36' 
?> 

正如我们在上面看到的


1) 如果你只关心字符串中有什么，使用 count_chars($string, 1)，它将返回一个（关联？）数组，其中只包含出现过的内容。


2) 要么是我误解了手册中实际描述的内容，要么它没有按照描述的方式工作：count_chars($strting, 3) 实际上返回的是字符串中有哪些字符的字符串，而不是它们的字节值的字符串（这很棒，因为数字字符串将更难处理）；


3) 这是一个简短的密码检查版本：获取原始字符串的长度，然后将其与 count_chars($string,3) 返回的字符串长度进行比较。


<?php 
$length_of_string = strlen($string); 
$num_of_chars = strlen(count_chars($string, 3)); 
 
$diff = ($length_of_string - $num_of_chars); 
 
if ($diff) 
echo 'At least one character has been used more than once.'; 
else 
echo 'All character have been used only once.'; 
?> 

请注意，由于 $num_of_chars 不会提供有关实际出现次数的信息，因此我们无法用相同的推理进一步推断，例如，当 $diff = 2 时，表示两个字符出现了两次；它可能是 1 个字符出现了 3 次，我们无法确定（不过，这是一个很好的容差级别设置器）。如果你想获得更多控制权，你需要获取数组并检查值。


4) 最后一个小技巧：现在我们有了一种原始的方法来计算字符串中单词的数量！（或者我们已经有一个函数可以做到这一点？）

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-12

apinpratap at gmail dot com ¶

17 years ago

这段代码可以找到每个字符的计数

<?php
$enter = 0;
$data = strtolower ($inputString);
foreach (count_chars ($data, 1) as $i => $val) 
 {
 if ($enter == 1)
 {
 $enter = 0;
 continue;
 }
 if (chr ($i) == "\n")
 {
 echo "There are $val instance(s) of \" Enter \" in the string.\n";
 $enter = 1;
 }
 else
 {
 echo "There are $val instance(s) of \"" , chr ($i) , "\" in the string.\n";
 }
 }
?>

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