如何添加包含每个数字列平均值的行

Question

我有一个汇总为数据透视表的数据框，我想添加一行，其中包含每个数字列的平均值，对于字符列，该行可以命名为“平均值”

示例数据框如下

dat <- c('2000-01-15','2003-01-15','2000-02-15',
         '2003-02-15','2000-04-15','2002-04-15',
         '2000-12-15','2002-12-15','2003-12-13', "2003-12-15",'2002-02-21','2002-01-25','2003-04-24')

df <- data.frame(date =as.Date(dat), id = c(1,2,3,4,5,6,7,8,9,10,11,12,13),
                 sales = c(134,211,2000,234,421,400,34,1233,1222,1034,8034,1234,2331))

df <- df %>% 
  mutate(year = format(date, "%Y"),
                    month = format(date, "%b")) %>% select(-date) %>%
  group_by(year,month) %>%
  summarise(revenue = sum(sales))

df2 <- df %>% pivot_wider(id_cols = year, names_from = month, values_from = revenue)

从这里我想做

rbind(df2, summarise_all(df2, mean))

然而，主要的复杂性在于如何仅返回数字列的平均值并返回非数字列的字符。

我想要的输出应该是

  year    Apr   Dec   Feb   Jan
  <chr> <dbl> <dbl> <dbl> <dbl>
1 2000    421    34  2000   134
2 2002    400  1233  8034  1234
3 2003   2331  2256   234   211
4 mean   1051. 1174. 3423.  526.

Answer 1

我们可以adorn_totals在末尾添加一个总和行，然后除以总行数 - 1

library(dplyr)
library(janitor)
df2 %>% 
    adorn_totals(name = "mean") %>%
    mutate(across(where(is.numeric), 
          ~ replace(., n(), .[n()]/(n()-1)))) %>%
    as_tibble

-输出

# A tibble: 4 x 5
  year    Apr   Dec   Feb   Jan
  <chr> <dbl> <dbl> <dbl> <dbl>
1 2000   421    34  2000   134 
2 2002   400  1233  8034  1234 
3 2003  2331  2256   234   211 
4 mean  1051. 1174. 3423.  526.

或者另一种选择是使用summarisewith在末尾across连接 ( c()) 一个值mean

df2 %>%
    ungroup %>% 
    summarise(year = c(year, 'mean'),
         across(where(is.numeric), ~ c(., mean(.))))

-输出

# A tibble: 4 x 5
  year    Apr   Dec   Feb   Jan
  <chr> <dbl> <dbl> <dbl> <dbl>
1 2000   421    34  2000   134 
2 2002   400  1233  8034  1234 
3 2003  2331  2256   234   211 
4 mean  1051. 1174. 3423.  526.

或者使用add_row来自tibble

library(tibble)
df2 %>% 
   ungroup %>% 
   add_row(year = 'mean', !!! colMeans(.[-1]))
# A tibble: 4 x 5
  year    Apr   Dec   Feb   Jan
  <chr> <dbl> <dbl> <dbl> <dbl>
1 2000   421    34  2000   134 
2 2002   400  1233  8034  1234 
3 2003  2331  2256   234   211 
4 mean  1051. 1174. 3423.  526.