Question

我使用select dplyr函数遇到奇怪的行为。它不会从数据框中删除变量。

以下是原始数据：

orig <- structure(list(park = structure(c(4L, 4L, 4L, 4L, 4L), .Label = c("miss", 
"piro", "sacn", "slbe"), class = "factor"), year = c(2006L, 2009L, 
2006L, 2008L, 2009L), agent = structure(c(5L, 5L, 5L, 7L, 5L), .Label = c("agriculture", 
"beaver", "development", "flooding", "forest_pathogen", "harvest_00_20", 
"harvest_30_60", "harvest_70_90", "none"), class = "factor"), 
    ha = c(4.32, 1.17, 3.51, 2.07, 9.18), loc_01 = structure(c(9L, 
    5L, 9L, 5L, 5L), .Label = c("miss", "non_miss", "non_piro", 
    "non_sacn", "non_slbe", "none", "piro", "sacn", "slbe"), class = "factor"), 
    loc_02 = structure(c(5L, 1L, 5L, 1L, 1L), .Label = c("none", 
    "piro_core", "piro_ibz", "slbe_mainland", "slbe_southmanitou"
    ), class = "factor"), loc_03 = structure(c(1L, 1L, 1L, 1L, 
    1L), .Label = "none", class = "factor"), cross_valid = c(1L, 
    1L, 1L, 1L, 1L)), .Names = c("park", "year", "agent", "ha", 
"loc_01", "loc_02", "loc_03", "cross_valid"), row.names = c(NA, 
5L), class = "data.frame")

看起来像：

> orig
  park year           agent   ha   loc_01            loc_02 loc_03 cross_valid
1 slbe 2006 forest_pathogen 4.32     slbe slbe_southmanitou   none           1
2 slbe 2009 forest_pathogen 1.17 non_slbe              none   none           1
3 slbe 2006 forest_pathogen 3.51     slbe slbe_southmanitou   none           1
4 slbe 2008   harvest_30_60 2.07 non_slbe              none   none           1
5 slbe 2009 forest_pathogen 9.18 non_slbe              none   none           1
> str(orig)
'data.frame':   5 obs. of  8 variables:
 $ park       : Factor w/ 4 levels "miss","piro",..: 4 4 4 4 4
 $ year       : int  2006 2009 2006 2008 2009
 $ agent      : Factor w/ 9 levels "agriculture",..: 5 5 5 7 5
 $ ha         : num  4.32 1.17 3.51 2.07 9.18
 $ loc_01     : Factor w/ 9 levels "miss","non_miss",..: 9 5 9 5 5
 $ loc_02     : Factor w/ 5 levels "none","piro_core",..: 5 1 5 1 1
 $ loc_03     : Factor w/ 1 level "none": 1 1 1 1 1
 $ cross_valid: int  1 1 1 1 1

然后我做了一点总结...

    library (dplyr)
    summ <- orig %>%
    + group_by(park,cross_valid,agent) %>%
    + summarise(ha_dist=sum(ha))
    summ
    Source: local data frame [2 x 4]
    Groups: park, cross_valid

      park cross_valid           agent ha_dist
    1 slbe           1 forest_pathogen   18.18
    2 slbe           1   harvest_30_60    2.07
    str(summ)
    Classes ‘grouped_df’, ‘tbl_df’, ‘tbl’ and 'data.frame': 2 obs. of  4 variables:
     $ park       : Factor w/ 4 levels "miss","piro",..: 4 4
     $ cross_valid: int  1 1
     $ agent      : Factor w/ 9 levels "agriculture",..: 5 7
     $ ha_dist    : num  18.18 2.07
     - attr(*, "vars")=List of 2
      ..$ : symbol park
      ..$ : symbol cross_valid
     - attr(*, "drop")= logi TRUE

然后我尝试删除＆＃39; cross_valid＆＃39; ...

sel <- select (summ,-cross_valid)
summ
Source: local data frame [2 x 4]
Groups: park, cross_valid

  park cross_valid           agent ha_dist
1 slbe           1 forest_pathogen   18.18
2 slbe           1   harvest_30_60    2.07
str(summ)
Classes ‘grouped_df’, ‘tbl_df’, ‘tbl’ and 'data.frame': 2 obs. of  4 variables:
 $ park       : Factor w/ 4 levels "miss","piro",..: 4 4
 $ cross_valid: int  1 1
 $ agent      : Factor w/ 9 levels "agriculture",..: 5 7
 $ ha_dist    : num  18.18 2.07
 - attr(*, "vars")=List of 2
  ..$ : symbol park
  ..$ : symbol cross_valid
 - attr(*, "drop")= logi TRUE
 - attr(*, "indices")=List of 1
  ..$ : int  0 1
 - attr(*, "group_sizes")= int 2
 - attr(*, "biggest_group_size")= int 2
 - attr(*, "labels")='data.frame':  1 obs. of  2 variables:
  ..$ park       : Factor w/ 4 levels "miss","piro",..: 4
  ..$ cross_valid: int 1
  ..- attr(*, "vars")=List of 2
  .. ..$ : symbol park
  .. ..$ : symbol cross_valid

它不会放弃summ$cross_valid

如果我使用基数R来删除cross_valid，它可以工作......

base.sel <- summ[-2]
base.sel
Source: local data frame [2 x 3]
Groups: 

  park           agent ha_dist
1 slbe forest_pathogen   18.18
2 slbe   harvest_30_60    2.07

我可以使用select ...

删除orig$cross_valid

drop.orig <- select (orig,-cross_valid)
drop.orig
  park year           agent   ha   loc_01            loc_02 loc_03
1 slbe 2006 forest_pathogen 4.32     slbe slbe_southmanitou   none
2 slbe 2009 forest_pathogen 1.17 non_slbe              none   none
3 slbe 2006 forest_pathogen 3.51     slbe slbe_southmanitou   none
4 slbe 2008   harvest_30_60 2.07 non_slbe              none   none
5 slbe 2009 forest_pathogen 9.18 non_slbe              none   none

由于我可以使用基数R删除变量，因此它不是什么大问题，但我认为dplyr可能存在一些问题。它可能是变量结构的东西，但我不知道它会是什么。

谢谢..

-cherrytree

Answer 1

尝试ungroup()

summ%>% 
ungroup() %>%
select(-cross_valid)
#  park           agent ha_dist
#1 slbe forest_pathogen   18.18
#2 slbe   harvest_30_60    2.07



groups(summ)
#[[1]]
#park

#[[2]]
#cross_valid

dplyr中select的奇怪行为

1 个答案: