从特定列的数据框中计算每行的多个均值

Question

我想为每四列计算此数据框中每一行的平均值。

    structure(list(Item = c("PPPG01050.1", "PPPG01080.1", "PPPG01090.1"
), C_Day1_WT1 = c(296160000, 552080000, 2560300000), C_Day1_WT2 = c(215080000, 
                                                                    605270000, 1507200000), C_Day1_WT3 = c(0, 372940000, 2524800000
                                                                    ), C_Day1_WT4 = c(0, 445260000, 2239800000), C_Day1_CCV1 = c(0, 
                                                                                                                                 365160000, 2018600000), C_Day1_CCV2 = c(0, 448180000, 2576900000
                                                                                                                                 ), C_Day1_CCV3 = c(0, 582880000, 1820900000), C_Day1_CCV4 = c(0, 
                                                                                                                                                                                               393070000, 1.925e+09), C_Day2_WT1 = c(369260000, 639450000, 2125500000
                                                                                                                                                                                               ), C_Day2_WT2 = c(0, 376960000, 1645700000), C_Day2_WT3 = c(441210000, 
                                                                                                                                                                                                                                                           456260000, 2694300000), C_Day2_WT4 = c(240700000, 584580000, 
                                                                                                                                                                                                                                                                                                  2145200000), C_Day2_CCV1 = c(0, 586700000, 1906300000), C_Day2_CCV2 = c(357200000, 
                                                                                                                                                                                                                                                                                                                                                                          527120000, 2441700000), C_Day2_CCV3 = c(114700000, 411270000, 
                                                                                                                                                                                                                                                                                                                                                                                                                  1637200000), C_Day2_CCV4 = c(98765000, 289370000, 1540600000), 
C_Day3_WT1 = c(272120000, 664570000, 2633400000), C_Day3_WT2 = c(432050000, 
                                                                 372230000, 2269700000), C_Day3_WT3 = c(326660000, 577260000, 
                                                                                                        1894100000), C_Day3_WT4 = c(332330000, 645940000, 1924300000
                                                                                                        ), C_Day3_CCV1 = c(156920000, 695450000, 936200000), C_Day3_CCV2 = c(249730000, 
                                                                                                                                                                             619140000, 1126500000), C_Day3_CCV3 = c(317850000, 525230000, 
                                                                                                                                                                                                                     1394700000), C_Day3_CCV4 = c(180140000, 463630000, 1641200000
                                                                                                                                                                                                                     ), C_Day4_WT1 = c(0, 0, 0), C_Day4_WT2 = c(0, 0, 2665900000
                                                                                                                                                                                                                     ), C_Day4_WT4 = c(0, 779120000, 1024400000), C_Day4_CCV1 = c(0, 
                                                                                                                                                                                                                                                                                  0, 1406800000), C_Day4_CCV2 = c(256840000, 669830000, 1452200000
                                                                                                                                                                                                                                                                                  ), C_Day4_CCV3 = c(302730000, 529320000, 1018200000), C_Day4_CCV4 = c(213970000, 
                                                                                                                                                                                                                                                                                                                                                        513700000, 1003300000), P_Day1_WT1 = c(0, 345700000, 2619900000
                                                                                                                                                                                                                                                                                                                                                        ), P_Day1_WT2 = c(0, 0, 0), P_Day1_WT3 = c(0, 666780000, 
                                                                                                                                                                                                                                                                                                                                                                                                   2020700000), P_Day1_WT4 = c(0, 397790000, 2038100000), P_Day1_CCV1 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                          306270000, 1581500000), P_Day1_CCV2 = c(430770000, 492330000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  2801800000), P_Day1_CCV3 = c(276210000, 602960000, 2547600000
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ), P_Day1_CCV4 = c(0, 268450000, 2359500000), P_Day2_WT1 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               514390000, 2486900000), P_Day2_WT2 = c(358710000, 477030000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      2828200000), P_Day2_WT3 = c(0, 187190000, 2.283e+09), P_Day2_WT4 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           321850000, 2321300000), P_Day2_CCV1 = c(0, 376680000, 2.251e+09
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           ), P_Day2_CCV2 = c(0, 376450000, 3247200000), P_Day2_CCV3 = c(190410000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         408790000, 1997100000), P_Day2_CCV4 = c(372620000, 316680000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 2898100000), P_Day3_WT1 = c(534270000, 578150000, 2232200000
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 ), P_Day3_WT2 = c(244510000, 638660000, 1399200000), P_Day3_WT3 = c(294660000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     508260000, 2248900000), P_Day3_WT4 = c(453780000, 521150000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            1816600000), P_Day3_CCV1 = c(305890000, 451130000, 2483900000
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            ), P_Day3_CCV2 = c(439220000, 771130000, 2477800000), P_Day3_CCV3 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  434490000, 2352500000), P_Day3_CCV4 = c(84403000, 354070000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          1.29e+09), P_Day4_WT1 = c(243900000, 346050000, 2630100000
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          ), P_Day4_WT2 = c(206100000, 272760000, 2810700000), P_Day4_WT3 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              508280000, 1505900000), P_Day4_WT4 = c(0, 332080000, 2410800000
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              ), P_Day4_CCV1 = c(0, 0, 2053600000), P_Day4_CCV2 = c(0, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    422370000, 2906300000), P_Day4_CCV3 = c(435900000, 456150000, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            2854400000), P_Day4_CCV4 = c(0, 278450000, 2883700000)), row.names = c(NA, 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   3L), class = "data.frame")

好吧，一般模式是这样的：

前 4 列加在一起：| C_Day1_WT1:C_Day1_WT4 |平均值 = colname(C_Day1_WT) 接下来的 4 列一起：| C_Day1_CCV1 : C_Day1_CCV4 |平均值 = colname(C_Day1_CCV)

等等。一般来说，新的data.frame 应该包含比原始数据少 4 倍的列。

问题：总共只有 63 列包含数字，因为缺少 C_Day4_WT3 列，这表明对于 C_Day4_WT 将只有三个重复。

我知道如何通过使用grep 函数对列进行子集化并对每一行使用apply 来循环分析它。但是，我想避免循环。

我会在等待回复的同时尝试编写一个循环。

Answer 1

关于 tidyverse 的建议：

df %>% gather(k,v,-Item) %>%                       # transform into tuples
  mutate(k1=str_extract(k,".*(?=\\d$)")) %>%       # get the name of the group of variables
  group_by(Item,k1) %>% summarise(sum=mean(v)) %>% # compute the means 
  spread(k1,sum) %>%                               # go back as an usual data frame 
  inner_join(df,by="Item")                         # and merge to the original

Answer 2

这里是 data.table 库的解决方案：

library(data.table)

df <- data.table(df)
df1 <- transpose(df[, -1])[, dd:=substring(colnames(df)[-1],1,9)][,.(Mean1=mean(V1), Mean2=mean(V2), Mean3=mean(V3)),.(dd) ]
output <- transpose(df1)