The CLP recognizes' null '(specified in uppercase characters) as a null string. For example.

CLP将“NULL”(以大写字符指定)识别为空字符串。

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It returns a null if no match is found, or if the source string is null or empty.

如果没有发现匹配项或源字符串是null或空，则返回null。

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It returns null if the source string is null or empty.

如果源字符串是null或空，则将返回null。

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NULL If a get string returns null, that pretty much means something went wrong and there are a few things that could go wrong.

如果GetSting返回，大致上表示的是出错了,这里有几种出错的地方。

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