根据整行使用dplyr / magrittr过滤行 [英] Filter rows with dplyr/magrittr based on entire row

问题描述

一个能够使用 filter 使用dplyr过滤行，但是条件通常基于每行的特定列，例如

One is able to filter rows with dplyr with filter, but the condition is usually based on specific columns per row such as

d <- data.frame(x=c(1,2,NA),y=c(3,NA,NA),z=c(NA,4,5))
d %>% filter(!is.na(y))

我想通过NA是否大于50％来过滤行，例如

I want to filter the row by whether the number of NA is greater than 50%, such as

d %>% filter(mean(is.na(EACHROW)) < 0.5 )

我该怎么做

推荐答案

您可以使用 rowSums 或 rowMeans 。提供的数据的示例：

You could use rowSums or rowMeans for that. An example with the provided data:

> d
   x  y  z
1  1  3 NA
2  2 NA  4
3 NA NA  5

# with rowSums:
d %>% filter(rowSums(is.na(.))/ncol(.) < 0.5)

# with rowMeans:
d %>% filter(rowMeans(is.na(.)) < 0.5)

都给出：

  x  y  z
1 1  3 NA
2 2 NA  4

如您所见，第3行已从数据中删除。

As you can see row 3 is removed from the data.

在基数R中，您可以做到：

In base R, you could just do:

d[rowMeans(is.na(d)) < 0.5,]

以获得相同的结果。

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