在R中将长列表分为短列表 [英] Divide long list into shorter lists in R

问题描述

我有一长串对象，我需要将它们分成较小的列表，每个列表有20个条目.要注意的是，每个对象只能在一个列表中出现一次.

I have a long list of objects that I need to divide into smaller lists, each with 20 entries. The catch is that each object can only appear once in a single list.

# Create some example data... 
# Make a list of objects.
LIST <- c('Oranges', 'Toast', 'Truck', 'Dog', 'Hippo', 'Bottle', 'Hope', 'Mint', 'Red', 'Trees', 'Watch', 'Cup', 'Pencil', 'Lunch', 'Paper', 'Peanuts', 'Cloud', 'Forever', 'Ocean', 'Train', 'Fork', 'Moon', 'Horse', 'Parrot', 'Leaves', 'Book', 'Cheese', 'Tin', 'Bag', 'Socks', 'Lemons', 'Blue', 'Plane', 'Hammock', 'Roof', 'Wind', 'Green', 'Chocolate', 'Car', 'Distance')

# Generate a longer list, with a random sequence and number of repetitions for each entry
LONG.LIST <- data.frame(Name = (sample(LIST, size = 200, replace = TRUE)))

print(LONG.LIST)

Name
1         Cup
2    Distance
3        Roof
4      Pencil
5       Lunch
6       Toast
7       Watch
8      Bottle
9         Car
10       Roof
11      Lunch
12    Forever
13     Cheese
14    Oranges
15      Ocean
16  Chocolate
17      Socks
18     Leaves
19    Oranges
20   Distance
21      Green
22      Paper
23        Red
24      Paper
25      Trees
26  Chocolate
27     Bottle
28        Dog
29       Wind
30     Parrot
etc....

使用上面生成的示例，'Distance'出现在位置'2'和位置'20'处，'Lunch'出现在'5'和'11处，'Oranges'出现在'14'和19'处，第一个没有重复的列表将需要扩展为包括'Green'，'Paper'和'Red'.然后，第二个列表将从'Paper'在位置24开始.

Using the example generated above, 'Distance' appears at both position '2' and position '20', 'Lunch' at both '5' and '11, and 'Oranges' at '14' and 19', so the first list without duplicates would need to extend to include 'Green', 'Paper' and 'Red'. The second list would then begin with 'Paper' at position 24.

最后一个列表可能不完整，因此最好用'NA'填充

The last list is likely to be incomplete, so it would be good to pad it with 'NA's

如果输出是单个数据帧中的列，那将是最简单的.

It would be simplest if the output were columns in a single data frame.

我什至不知道从哪里开始，所以真的很感谢任何建议.谢谢！

I've no idea where to even start with this, so any suggestions are really appreciated. Thanks!

推荐答案

我们可以使用tidyverse做到这一点.按名称"分组，创建一个包含序列号的列，我们在group_by中使用该列创建一个新的序列列"ind"，然后使用spread和order列按字母顺序将其转换为宽"格式

We can do this with tidyverse. Grouped by 'Name', create a column with sequence numbers, that we use in group_by to create a new sequence column 'ind', then convert to 'wide' format with spread and order the columns alphabetically

library(tidyverse)
LONG.LIST %>%
   group_by(Name) %>%
   mutate(grp = row_number()) %>%
   group_by(grp) %>% 
   mutate(ind = row_number()) %>% 
   spread(grp, Name) %>%
   mutate_at(vars(-one_of("ind")), funs(.[order(as.character(.))]))
# A tibble: 40 x 12
#     ind       `1`       `2`      `3`      `4`      `5`      `6`      `7`      `8`      `9`     `10`     `11`
#   <int>    <fctr>    <fctr>   <fctr>   <fctr>   <fctr>   <fctr>   <fctr>   <fctr>   <fctr>   <fctr>   <fctr>
# 1     1       Bag       Bag      Bag      Bag      Bag      Bag      Bag      Bag      Cup Distance Distance
# 2     2      Blue      Blue     Book     Book     Book    Cloud      Cup      Cup Distance    Train       NA
# 3     3      Book      Book   Bottle    Cloud    Cloud      Cup Distance Distance    Train       NA       NA
# 4     4    Bottle    Bottle   Cheese      Cup      Cup Distance      Dog  Hammock       NA       NA       NA
# 5     5       Car       Car    Cloud Distance Distance      Dog  Hammock     Moon       NA       NA       NA
# 6     6    Cheese    Cheese      Cup      Dog      Dog  Hammock     Moon   Parrot       NA       NA       NA
# 7     7 Chocolate Chocolate Distance     Fork  Hammock    Horse    Paper    Train       NA       NA       NA
# 8     8     Cloud     Cloud      Dog  Hammock    Horse     Moon   Parrot       NA       NA       NA       NA
# 9     9       Cup       Cup     Fork    Hippo     Mint    Paper    Train       NA       NA       NA       NA
#10    10  Distance  Distance    Green    Horse     Moon   Parrot       NA       NA       NA       NA       NA
# ... with 30 more rows

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