count_chars
(PHP 4, PHP 5, PHP 7, PHP 8)
count_chars — 文字列で使用されている文字に関する情報を返す
説明
string において各バイト値 (0..255)
が存在する数をかぞえ、様々な手法で返します。
パラメータ
string-
調べたい文字列。
mode-
戻り値を参照ください。
戻り値
mode の値により、
count_chars() は以下の値のどれかを返します。
- 0 - 各バイト値をキー、各バイトの出現回数を値とする配列。
- 1 - 0と同じですが、各バイト値の出現回数がゼロより大きいものの一覧となります。
- 2 - 0と同じですが、各バイト値の出現回数がゼロであるものの一覧となります。
- 3 - すべての一意な文字を含む文字列を返します。
- 4 - 使用されていない全ての文字を含む文字列を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 8.0.0 |
これより前のバージョンでは、この関数は失敗時に false を返していました。
|
例
例1 count_chars() の例
<?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";
}
?>上の例の出力は以下となります。
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.
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User Contributed Notes 8 notes
marcus33cz ¶
12 years ago
If you have problems using count_chars with a multibyte string, you can change the page encoding. Alternatively, you can also use this mb_count_chars version of the function. Basically it is mode "1" of the original function.
<?php
/**
* Counts character occurences in a multibyte string
* @param string $input UTF-8 data
* @return array associative array of characters.
*/
function mb_count_chars($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 )
?>
Eric Pecoraro ¶
19 years ago
<?php
// Require (n) unique characters in a string
// Modification of a function below which ads some flexibility in how many unique characters are required in a given string.
$pass = '123456' ; // true
$pass = '111222' ; // false
req_unique($pass,3);
function req_unique($string,$unique=3) {
if ( count(count_chars($string,1)) < $unique) {
echo 'false';
}else{
echo 'true';
}
}
?>
seb at synchrocide dot net ¶
20 years ago
After much trial and error trying to create a function that finds the number of unique characters in a string I same across count_chars() - my 20+ lines of useless code were wiped for this:
<?
function unichar($string) {
$two= strtolower(str_replace(' ', '', $string));
$res = count(count_chars($two, 1));
return $res;
}
/* examples :: */
echo unichar("bob"); // 2
echo unichar("Invisibility"); //8
echo unichar("The quick brown fox slyly jumped over the lazy dog"); //26
?>
I have no idea where this could be used, but it's quite fun
Anonymous ¶
8 years ago
count_chars for multibyte supported.
<?php
function mb_count_chars ($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 $result;
}
?>
Andrey G ¶
4 years ago
Checking that two strings are anagram:
<?php
function isAnagram($string1, $string2)
{
return count_chars($string1, 1) === count_chars($string2, 1);
}
isAnagram('act', 'cat'); // true
?>
pzb at novell dot com ¶
17 years ago
This function is great for input validation. I frequently need to check that all characters in a string are 7-bit ASCII (and not null). This is the fastest function I have found yet:
<?php
function is7bit($string) {
// empty strings are 7-bit clean
if (!strlen($string)) {
return true;
}
// count_chars returns the characters in ascending octet order
$str = count_chars($str, 3);
// Check for null character
if (!ord($str[0])) {
return false;
}
// Check for 8-bit character
if (ord($str[strlen($str)-1]) & 128) {
return false;
}
return true;
}
?>
phpC2007 ¶
17 years ago
Here's a function to count number of strings in a string. It can be used as a simple utf8-enabled count_chars (but limited to a single mode)...
<?php
function utf8_count_strings($stringChar)
{
$num = -1;
$lenStringChar = strlen($stringChar);
for ($lastPosition = 0;
$lastPosition !== false;
$lastPosition = strpos($textSnippet, $stringChar, $lastPosition + $lenStringChar))
{
$num++;
}
return $num;
}
?>
mlong at mlong dot org ¶
22 years ago
// Usefulness of the two functions
<?php
$string="aaabbc";
// You just want to count the letter a
$acount=substr_count($string,"a");
// You want to count both letter a and letter b
$counts=count_chars($string,0);
$acount=$counts[ord("a")];
$bcount=$counts[ord("b")];
?>