程式設計@筆記

[php] count_chars — 返回字符串所用字符的信息

統計 string 中每個字節值（0..255）出現的次數，使用多種模式返回結果。可選參數 mode 默認值為 0。根據不同的 mode，count_chars() 返回下列不同的結果：

• 0 - 以所有的每個字節值作為鍵名，出現次數作為值的數組。
• 1 - 與 0 相同，但只列出出現次數大於零的字節值。
• 2 - 與 0 相同，但只列出出現次數等於零的字節值。
• 3 - 返回由所有使用了的字節值組成的字符串。
• 4 - 返回由所有未使用的字節值組成的字符串。

官方範例
<?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";
}
?>

以上例程會輸出：

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.



範例一

在本例中，我們將使用 count_chars() 來檢查字符串，返回模式設置為 1：

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

輸出：

Array
(
[32] => 1
[33] => 1
[72] => 1
[87] => 1
[100] => 1
[101] => 1
[108] => 3
[111] => 2
[114] => 1
)

範例二

在本例中，我們將使用 count_chars() 來檢查字符串，返回模式設置為 3：

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

輸出：

 !HWdelor