php返回字串所有資訊的函數count_chars()

執行個體

返回一個字串，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() 函數返回字串所用字元的資訊（例如，ASCII 字元在字串中出現的次數，或者某個字元是否已經在字串中使用過）。

文法

count_chars(string,mode)

參數 描述

string 必需。規定要檢查的字串。

mode 可選。規定返回模式。預設是 0。有以下不同的返回模式：

0 - 數組，ASCII 值為鍵名，出現的次數為索引值

1 - 數組，ASCII 值為鍵名，出現的次數為索引值，只列出出現次數大於 0 的值

2 - 數組，ASCII 值為鍵名，出現的次數為索引值，只列出出現次數等於 0 的值

3 - 字串，帶有所有使用過的不同的字元

4 - 字串，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+

更多執行個體

執行個體 1

返回一個字串，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);?>

執行個體 2

在本執行個體中，我們將使用 count_chars() 來檢查字串，返回模式設定為 1。模式 1 將返回一個數組，ASCII 值為鍵名，出現的次數為索引值：

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

執行個體 3

統計 ASCII 字元在字串中出現的次數另一個執行個體：

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

count_chars執行個體

<?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/>" ;}?>

運行結果：

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.