PHP function count_chars() that returns all information of a string

Example

Returns a string containing all the different characters used in "Hello World!" (mode 3):

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

Definition and usage

count_chars() FunctionReturns information about the characters used in a string (for example, the number of times an ASCII character appears in a string, or whether a character has already been used in a string).

Syntax

count_chars(string,mode)

Parameters                                                                                                                                                                                                                            . Specifies the string to check. ​

mode ​ ​ ​ ​ ​ Optional. Specifies the return mode. The default is 0. There are different return patterns: , the number of occurrences is the key value, only the values ​​with the number of occurrences greater than 0 are listed

                2 - Array, the ASCII value is the key name, the number of occurrences is the key value, only the values ​​with the number of occurrences equal to 0 are listed

3 -String, with all different characters that have been used 4 -String, with all unused different characters

Technical details

Return value: Depends on the specified mode parameter.

PHP Version: 4+

More examples

Example 1

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

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

Example 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.

The above is the detailed content of PHP function count_chars() that returns all information of a string. For more information, please follow other related articles on the PHP Chinese website!