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ctype_alnum()が整数を通してくれない

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英数字かどうかを調べるのにctype_alnum()を使用していると、
このコードがfalseを返してくる

ctype_alnum(1);

マニュアルを見返すと

bool ctype_alnum ( string $text )

mixedじゃない...

ctype_alnum('1');

これなら通りました。

この手の関数、大体引数mixedだと思っていたら、
思わぬ落とし穴にはまりました。

ma_me
ペチパーから卒業したい
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