当列名称-值对存储在列表中时过滤数据框?
我有一个数据框,如:
df <- tibble::rownames_to_column(USArrests, "State") %>%
tidyr::pivot_longer(cols = -State)
head(df)
# A tibble: 6 x 3
State name value
<chr> <chr> <dbl>
1 Alabama Murder 13.2
2 Alabama Assault 236
3 Alabama UrbanPop 58
4 Alabama Rape 21.2
5 Alaska Murder 10
6 Alaska Assault 263
在一个单独的列表对象中,l我有列,我需要从数据框中删除。元素名称是列名称,值对应于我要删除的行:
l <- list(State = c("Alabama", "Pennsylvania", "Texas"),
name = c("Murder", "Assault"))
硬编码它会这样做:
dplyr::filter(df, !State %in% c("Alabama", "Pennsylvania", "Texas"), !name %in% c("Murder", "Assault"))
State name value
<chr> <chr> <dbl>
1 Alaska UrbanPop 48
2 Alaska Rape 44.5
3 Arizona UrbanPop 80
4 Arizona Rape 31
5 Arkansas UrbanPop 50
6 Arkansas Rape 19.5
7 California UrbanPop 91
8 California Rape 40.6
9 Colorado UrbanPop 78
10 Colorado Rape 38.7
# ... with 84 more rows
但是,l经常更改,因此我不能/不想进行硬编码。我尝试了以下操作,但只计算最后一个表达式:
library(purrr)
filter_expr <- imap_chr(l, ~ paste0("! ",
.y,
" %in% c("",
paste(.x, collapse = "",""),
"")")) %>% parse(text = .)
filter(df, eval(filter_expr))
State name value
<chr> <chr> <dbl>
1 Alabama UrbanPop 58
2 Alabama Rape 21.2
3 Alaska UrbanPop 48
4 Alaska Rape 44.5
5 Arizona UrbanPop 80
6 Arizona Rape 31
7 Arkansas UrbanPop 50
8 Arkansas Rape 19.5
9 California UrbanPop 91
10 California Rape 40.6
# ... with 90 more rows
df当过滤条件存储在类似ltidyverse 更惯用的结构中时,有没有办法进行过滤?
我认为这个SO answer,但是,表达式不是动态的。
回答
我们可以使用across在filter循环过names的子集化利用列名(该键的“L”为“l”,创建的逻辑表达式cur_column())和否定(!)。请注意,cur_column()目前仅适用于across和不适用if_all/if_any(dplyr- 1.0.6on R 4.1.0)
library(dplyr)
df %>%
filter(across(all_of(names(l)), ~ !. %in% l[[cur_column()]]))
-输出
# A tibble: 94 x 3
# State name value
# <chr> <chr> <dbl>
# 1 Alaska UrbanPop 48
# 2 Alaska Rape 44.5
# 3 Arizona UrbanPop 80
# 4 Arizona Rape 31
# 5 Arkansas UrbanPop 50
# 6 Arkansas Rape 19.5
# 7 California UrbanPop 91
# 8 California Rape 40.6
# 9 Colorado UrbanPop 78
#10 Colorado Rape 38.7
# … with 84 more rows
我们可以利用if_allif 我们可以设置一个属性
library(magrittr)
df %>%
mutate(across(all_of(names(l)), ~ set_attr(., 'cn', cur_column()))) %>%
filter(if_all(all_of(names(l)), ~ ! . %in% l[[attr(., 'cn')]]))
或与 imap/reduce
library(purrr)
df %>%
filter(imap(l, ~ !cur_data()[[.y]] %in% .x) %>%
reduce(`&`))
或者另一种选择是 anti_join
for(nm in names(l)) df <- anti_join(df, tibble(!! nm := l[[nm]]))