[英]Find rows where one column string is in another column using dplyr in R
希望拉回一列中的值作為另一列(同一行內)中的字符串存在的行。
我有一個 df:
A <- c("cat", "dog", "boy")
B <- c("cat in the cradle", "meet the parents", "boy mmets world")
df <- as.data.frame(A, B)
A B
cat cat in the cradle
dog meet the parents
boy boy meets world
我正在嘗試這樣的事情:
df2 <- df %>%
filter(grepl(A, B)) # doesn't work because it thinks A is the whole column vector
df2 <- df %>%
filter(B %in% A) # which doesn't work because it has to be exact
我想讓它產生
A B
cat cat in the cradle
boy boy meets world
提前致謝!
馬特
我們可以用Map
做到這一點
df[mapply(grepl, df$A, df$B),]
# A B
#1 cat cat in the cradle
#3 boy boy mmets world
使用tidyverse
,類似的選項是purrr::map2
with stringr::str_detect
library(tidyverse)
df %>%
filter(map2_lgl(B, A, str_detect))
# A B
#1 cat cat in the cradle
#2 boy boy mmets world
df <- data.frame(A, B, stringsAsFactors=FALSE)
您可以使用Map
將函數應用於兩個向量,也可以使用sapply
遍歷行
df %>%
filter(unlist(Map(function(x, y) grepl(x, y), A, B)))
A B
1 cat cat in the cradle
2 boy boy mmets world
df %>%
filter(sapply(1:nrow(.), function(i) grepl(A[i], B[i])))
A B
1 cat cat in the cradle
2 boy boy mmets world
為了完整起見,這可以使用str_detect
中的 str_detect 輕松完成
library(tidyverse)
df <- tibble(A, B) %>%
filter(str_detect(B, fixed(A)) == TRUE)
df
# A tibble: 2 x 2
# A B
# <chr> <chr>
#1 cat cat in the cradle
#2 boy boy mmets world
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