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信息: <blockquote data-quote="TAAAAAAA" data-source="post: 2354" data-attributes="member: 2783">Applying knowledge on inheritance trees 利用类的父子关系链This might sound useless, but it can actually come in handy.Where normally, to determine if a number is a Float or a Fixnum, we’d use var.is_a?(Float) || var.is_a?(Fixnum), their inheritance trees reveal this:Fixnum:这是整数类的父子关系链：Float:这是浮点数类的父子关系链：What we can gather from this, is that var.is_a?(Numeric) will be true for both Floats and Fixnums. You just have to know if any other classes use Numeric, but that isn’t the case, so it’s safe to use. If we did Comparable, for instance, we’d also get String in there, which we don’t want.我们可以利用哪些类是共有的，而哪些类是独有的，等等的关系，来检查对象。</blockquote>