This expression also removes all null characters and excess whitespace.

此表达式也会删除所有空字符和过量的空白。

youdao

For instance, you don't need to check whether the data contains null characters because an XML parser will never pass you a null.

例如，不需要检查数据是否包含空字符，因为XML解析器绝不会传送一个空值。

youdao

Normal control characters (characters with values less than 32) : This especially includes character 0, traditionally called NUL; I call it NIL to distinguish it from c's NULL pointer.

常规控制字符(字符值小于32)：还特别包括字符0，传统上称做NUL；我把它称为NIL以区别于c语言中的NULL指针。

youdao