基于行名的子集数据框

Question

I have two data frames ( bwenv and bwsp ). bwsp is a subset of bwenv and they have matching rownames (sample id). I would like to subset bwenv so that it only includes the rows that are also found in bwsp .

When the number of rows match, I have used:

bw2015 <- cbind(bwenv, bwsp)

to create a new dataframe with the combined data.

My question is very similar to the question asked here: R subset a column in data frame based on another data frame/list , but the subsetting is done by a column of data in each dataframe (rather than row names like I want to do).

Answer 1

library(dplyr)

bw2015 <- bwenv %>% 
  add_rownames("row_names") %>%
  semi_join(add_rownames(bwsp, "row_names"), by = "row_names")

Answer 2

Following on from @yeedle's solution, I modified it a little and found this worked for me:

library(dplyr)
bwenv2 <- bwenv %>% 
  rownames_to_column("row_names") %>%
  semi_join(rownames_to_column(bwsp, "row_names"), by = "row_names")
rownames(bwenv2) <- bwenv2$row_names 
bwenv2 <- bwenv2 %>% select(-row_names)

bw2015 <- cbind(bwenv2, bwsp)
str(bw2015)