Question

我有一个数据框，我想通过将两个现有行相乘来计算新行。我的数据框的结构如下：

structure(list(month = c("mazda", "yamaha", "car"), april = c(11, 
12, 0.1), may = c(14, 15, 0.5)), row.names = c(NA, -3L), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"), vars = "month", drop = TRUE, indices = list(
    2L, 0L, 1L), group_sizes = c(1L, 1L, 1L), biggest_group_size = 1L, labels = structure(list(
    month = c("car", "mazda", "yamaha")), row.names = c(NA, -3L
), class = "data.frame", vars = "month", drop = TRUE))

我想添加一行total，该行将是mazda和car的乘积。并且如果未找到行车，它应该位于新行0中的total。我想要达到的期望输出：

# A tibble: 4 x 3
# Groups:   month [4]
  month  april   may
  <chr>  <dbl> <dbl>
1 mazda   11    14  
2 yamaha  12    15  
3 car      0.1   0.5
4 total    1.1   7

Answer 1

这听起来确实/看起来像是XY问题。我建议您重新考虑一下您的常规代码和数据设计。例如，为什么第1列标记为month，却又包含条目"mazda"，"yamaha"，"car"和"total"？

对于它的价值，您可以使用来重现您的预期输出

rbind(df, c(month = "total", df[df$month == "mazda", -1] * df[df$month == "car", -1]))
## A tibble: 4 x 3
## Groups:   month [4]
#  month  april   may
#  <chr>  <dbl> <dbl>
#1 mazda   11    14
#2 yamaha  12    15
#3 car      0.1   0.5
#4 total    1.1   7

将同一数据帧中的两行相乘

1 个答案: