count_chars
(PHP 4, PHP 5, PHP 7)
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 -
返り値を参照ください。
返り値
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。
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.
忘却曲線を使ってこの関数を確実に記憶に残す
