当列包含因子时，使用OR子集数据框 [英] Subset a data frame using OR when the column contains a factor

问题描述

我想在R中制作一个数据帧的子集，该子集基于一列因子中的一个或另一个值，但看来我不能将|与因子值一起使用.

I would like to make a subset of a data frame in R that is based on one OR another value in a column of factors but it seems I cannot use | with factor values.

示例:

# fake data
x <- sample(1:100, 9)
nm <- c("a", "a", "a", "b", "b", "b", "c", "c", "c")
fake <- cbind(as.data.frame(nm), as.data.frame(x))
# subset fake to only rows with name equal to a or b
fake.trunk <- fake[fake$nm == "a" | "b", ]

产生错误:

Error in fake$nm == "a" | "b" : 
operations are possible only for numeric, logical or complex types

我该怎么做?

很明显，我的实际数据帧在factor列中有3个以上的值，因此仅使用!= "c"无效.

Obviously my actual data frame has more than 3 values in the factor column so just using != "c" won't work.

推荐答案

您需要fake.trunk <- fake[fake$nm == "a" | fake$nm == "b", ].一种更简洁的写法(尤其是具有两个以上的条件)是:

You need fake.trunk <- fake[fake$nm == "a" | fake$nm == "b", ]. A more concise way of writing that (especially with more than two conditions) is:

fake[ fake$nm %in% c("a","b"), ]

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