php傳回字串所有資訊的函數count_chars()

實例

傳回一個字串，包含所有在"Hello World!" 中使用過的不同字元（模式3）：

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

定義和用法

count_chars() 函數傳回字串所用字元的資訊（例如，ASCII 字元在字串中出現的次數，或某個字元是否已經在字串中使用過）。

文法

count_chars(string,mode)

參數                       說明

#string              規定要檢查的字串。    

mode                      選擇。規定返回模式。預設是 0。有以下不同的回傳模式：

                               0 - 陣列# #             1 - 數組，ASCII 值為鍵名，出現的次數為鍵值，只列出出現次數大於0 的值

                               2 - 陣列，ASCII 值為鍵名，出現時的次數為鍵值，

##                               3 - 字串，並使用所有使用過的不同的字元

# #  帶有所有未使用過的不同的字元

技術細節

傳回值：       取決於指定的 mode 參數。

PHP 版本：   4+    

更多實例

實例1

傳回字串，包含所有在"Hello World!" 中未使用過的字元（模式4）：

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

實例2

在本实例中，我们将使用 count_chars() 来检查字符串，返回模式设置为 1。模式 1 将返回一个数组，ASCII 值为键名，出现的次数为键值：

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

实例 3

统计 ASCII 字符在字符串中出现的次数另一个实例：

<?php
$str = "PHP is pretty fun!!";
$strArray = count_chars($str,1);

foreach ($strArray as $key=>$value)
{
echo "The character <b>&#39;".chr($key)."&#39;</b> was found $value time(s)<br>";
}
?>

count_chars实例

<?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.<br/>" ;
}
?>

运行结果：

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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