基准

Question

假设我有以下数据框和列表

import 'package:http/http.dart' as http;
...    
final response = await http.get(Url);

我想在列表中找到# data frames df1 = data.frame(y1 = c(1:5), y2 = c(8:12)) df2 = data.frame(y1 = c(5:8), y2 = c(9:12)) df3 = data.frame(y1 = c(5:8), y2 = c(9:12)) df4 = data.frame(y1 = c(11:15), y2 = c(16:20)) # list of data.frames my.list <- list(df1, df2, df3, df4)的位置，我尝试了一下，但得到了df1。我也尝试过NA，但遇到错误。

==

但是当我这样做时，我会得到结果

match(df1, my.list)
# [1] NA NA

我相信它与列表中的list14 = my.list[c(1,4)] match(list14, my.list) # [1] 1 4和[]标记有关。最终我想做类似的事情

[[]]

其中for (i in list14) { cbind(list14, "indexPositionOf_list14_in_my.list") }是indexPositionOf_list14_in_my.list中list14中相应data.frame的索引位置。

my.list循环的预期输出

for

Answer 1

也许是这样吗？

my.list<- mapply(cbind, my.list, id=seq_along(my.list), SIMPLIFY = FALSE)

my.list %>% 
  map(., inner_join, df3) %>% 
  map(., compact) %>% 
  compact()
#> Joining, by = c("y1", "y2")
#> Joining, by = c("y1", "y2")
#> Joining, by = c("y1", "y2")
#> Joining, by = c("y1", "y2")
#> [[1]]
#>   y1 y2 id
#> 1  5  9  2
#> 2  6 10  2
#> 3  7 11  2
#> 4  8 12  2
#> 
#> [[2]]
#>   y1 y2 id
#> 1  5  9  3
#> 2  6 10  3
#> 3  7 11  3
#> 4  8 12  3

Answer 2

您可以使用duplicated和mapply：

mapply(cbind, my.list, id=seq_along(my.list), SIMPLIFY = FALSE)[duplicated(my.list) | duplicated(my.list, fromLast = TRUE)]

[[1]]
  y1 y2 id
1  5  9  2
2  6 10  2
3  7 11  2
4  8 12  2

[[2]]
  y1 y2 id
1  5  9  3
2  6 10  3
3  7 11  3
4  8 12  3

基准

library(rbenchmark)

benchmark("baseR" = {
  mapply(cbind, my.list, id=seq_along(my.list), SIMPLIFY = FALSE)[duplicated(my.list) | duplicated(my.list, fromLast = TRUE)]

},
"map" = {
  mapply(cbind, my.list, id=seq_along(my.list), SIMPLIFY = FALSE) %>% 
    map(., inner_join, df3) %>% 
    map(., compact) %>% 
    compact()
},
replications = 1000,
columns = c("test", "replications", "elapsed",
            "relative", "user.self", "sys.self"))


  test replications elapsed relative user.self
1 baseR         1000    0.37    1.000      0.38
2   map         1000    4.82   13.027      4.80
  sys.self
1     0.00
2     0.02

如何获取data.frames列表中特定data.frame的索引？

2 个答案:

基准