为什么我会收到“警告较长的物体长度不是较短物体长度的倍数"? [英] Why do I get "warning longer object length is not a multiple of shorter object length"?

问题描述

我有数据框 dih_y2.这两行给了我一个警告:

I have dataframe dih_y2. These two lines give me a warning:

> memb = dih_y2$MemberID[1:10]
> dih_col = which(dih_y2$MemberID == memb)  
Warning message:
In dih_y2$MemberID == memb :
longer object length is not a multiple of shorter object length

为什么?

推荐答案

您没有给出可重现的示例，但您的警告消息会准确地告诉您问题所在.

You don't give a reproducible example but your warning message tells you exactly what the problem is.

memb 只有 10 的长度.我猜dih_y2$MemberID 的长度不是 10 的倍数.当使用 ==，如果不是倍数，R 会发出警告，让您知道它可能没有做您期望它做的事情.== 对元素进行相等性检查.我怀疑您想要做的是找到 dih_y2$MemberID 的哪些元素也在向量 memb 中.为此，您需要使用 %in% 运算符.

memb only has a length of 10. I'm guessing the length of dih_y2$MemberID isn't a multiple of 10. When using ==, R spits out a warning if it isn't a multiple to let you know that it's probably not doing what you're expecting it to do. == does element-wise checking for equality. I suspect what you want to do is find which of the elements of dih_y2$MemberID are also in the vector memb. To do this you would want to use the %in% operator.

dih_col <- which(dih_y2$MemeberID %in% memb)

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