删除小于 n 值的列?

本文介绍了删除小于 n 值的列?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

假设我有一个如下所示的数据框:

Suppose i have a data frame like the following:

df <- data.frame(v1 = sample(1:10, 100, replace = T), v2 = sample(LETTERS, 100, replace = T), V3 = sample(letters, 100, replace = T), v4 = sample(1:15, 100, replace = T))

我想创建一个新的数据框 df2 只包含取值超过 10 个的列.因此，在此示例中，它将是 v2、v3 和 v4.我怎样才能做到这一点?实际上，我的数据框有数千列.

I would like to create a new data frame df2 only includes the columns that take more than 10 values. So, in this example it would be v2, v3, and v4. How can I do that? In practice my data frame has thousands of columns.

我试过了:

df2 <- df %>% select(which(length(unique(.))>10))

推荐答案

或者，您可以使用 dplyr 中的 select_if()，您可以在其中将函数作为谓词传递给选择列:

Alternatively, you can use select_if() from dplyr where you can pass a function as predicate to select columns:

library(dplyr) df %>% select_if(function(col) n_distinct(col) > 10) # v2 V3 v4 #1 T a 12 #2 R k 7 #3 L l 1 # ...

或者在dplyr版本>=1.00

df %>% select(where(~ n_distinct(.) > 10))