R根据行中的值在列中重复

Question

我有一个如下所示的数据框：

Name    School   Weight Days
Antoine Bach     0.03   5
Antoine Ken      0.02   7
Barbara Franklin 0.04   3

我想获得如下输出：

Name    School   1    2    3    4    5    6    7
Antoine Bach     0.03 0.03 0.03 0.03 0.03 NA   NA
Antoine Ken      0.02 0.02 0.02 0.02 0.02 0.02 0.02
Barbara Franklin 0.04 0.04 0.04 NA   NA   NA   NA

可重现的样本数据：

df <- tribble(
  ~Name,    ~School,   ~Weight, ~Days,
  "Antoine", "Bach",     0.03,   5,
  "Antoine", "Ken",      0.02,   7,
  "Barbara", "Franklin", 0.04,   3
)

Answer 1

使用 data.table，您可以通过为每行多次rep读取Weight值来创建长版本，然后使用新变量的作为列来转换为宽格式。Daysdcastrowid

library(data.table)
setDT(df)

dcast(df[, .(rep(Weight, Days)), .(Name, School)], 
      Name + School ~ rowid(V1))

# Name   School    1    2    3    4    5    6    7
# 1: Antoine     Bach 0.03 0.03 0.03 0.03 0.03   NA   NA
# 2: Antoine      Ken 0.02 0.02 0.02 0.02 0.02 0.02 0.02
# 3: Barbara Franklin 0.04 0.04 0.04   NA   NA   NA   NA

您还可以rep Weight计算 的数量Days，然后重复NA足够的次数来完成该行。

max_days <- max(df$Days) 

df[, as.list(rep(c(Weight, NA), c(Days, max_days - Days))), 
   .(Name, School)]

# Name   School   V1   V2   V3   V4   V5   V6   V7
# 1: Antoine     Bach 0.03 0.03 0.03 0.03 0.03   NA   NA
# 2: Antoine      Ken 0.02 0.02 0.02 0.02 0.02 0.02 0.02
# 3: Barbara Franklin 0.04 0.04 0.04   NA   NA   NA   NA

Answer 2

我喜欢tidyr::uncount为每行制作x一定数量的副本。我们可以转动得更远，不计其数，然后再转动得更远。

library(tidyr)
my_data %>%
  pivot_longer(Weight) %>%
  uncount(Days, .id = "colnum") %>%
  dplyr::select(-name) %>%
  pivot_wider(names_from = colnum, values_from = value)


# A tibble: 3 x 9
  Name    School     `1`   `2`   `3`   `4`   `5`   `6`   `7`
  <chr>   <chr>    <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Antoine Bach      0.03  0.03  0.03  0.03  0.03 NA    NA   
2 Antoine Ken       0.02  0.02  0.02  0.02  0.02  0.02  0.02
3 Barbara Franklin  0.04  0.04  0.04 NA    NA    NA    NA