如何在 tidyverse 中使用表格？答案

【问题标题】：How to use tabulate in the tidyverse?如何在 tidyverse 中使用表格？
【发布时间】：2020-03-06 17:16:33
【问题描述】：

我想将那段旧代码转换为 tidyverse。有人可以帮忙吗？

library(plyr)
ddply(dat,.(sex),function(x) tabulate(x[,1],nbins=5))

# result
#     sex V1 V2 V3 V4 V5
#1 female  1  6  0  2  0
#2   male  2 11  3  0  0

dat <- structure(list(P1 = c(2, 2, 1, 2, 2, 2, 2, 1, 2, 4, 3, 2, 3, 
2, 2, 2, 4, 2, 2, 1, 2, 3, 2, 2, 2), sex = structure(c(2L, 2L, 
2L, 2L, 2L, 2L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 2L, 2L, 1L, 1L, 1L, 
2L, 2L, 2L, 2L, 1L, 1L, 1L), .Label = c("female", "male"), class = "factor")), class = "data.frame", row.names = c(NA, 
-25L))

【问题讨论】：

标签： r tidyverse

【解决方案1】：

library(tidyverse)

# set number of bins
nb = 5

dat %>%
  count(P1, sex) %>%                                # count combinations
  complete(P1 = 1:nb, sex, fill = list(n = 0)) %>%  # if a bin is missing add a zero count
  spread(P1, n, sep = "_")                          # reshape dataset

# # A tibble: 2 x 6
#   sex     P1_1  P1_2  P1_3  P1_4  P1_5
#   <fct>  <dbl> <dbl> <dbl> <dbl> <dbl>
# 1 female     1     6     0     2     0
# 2 male       2    11     3     0     0

【讨论】：

'retired' spread() 可以替换为：pivot_wider(names_from = P1, values_from = n, names_prefix = "P1_")

【解决方案2】：

在base R中，我们可以在将'P1'列转换为factor后使用table

table(transform(dat, P1 = factor(P1, levels = 1:5,
             labels = paste0("P1_", 1:5)))[2:1])
#       P1
#sex      P1_1 P1_2 P1_3 P1_4 P1_5
#  female    1    6    0    2    0
#  male      2   11    3    0    0

或者使用来自data.table的dcast

library(data.table)
dcast(setDT(dat), sex ~ factor(P1, levels = 1:5,
         labels = paste0("P1_", 1:5)), drop = FALSE, length)
#      sex P1_1 P1_2 P1_3 P1_4 P1_5
#1: female    1    6    0    2    0
#2:   male    2   11    3    0    0

【讨论】：