按组对变量求和并将其作为新变量添加到数据框中答案

【问题标题】：summing a variable by group and adding it as a new variable in a data frame按组对变量求和并将其作为新变量添加到数据框中
【发布时间】：2020-08-03 11:59:42
【问题描述】：

现在我有一个来自游戏日（标题：games_day）的数据框，看起来像这样

games day

我想在数据框中创建一个新变量，将每个团队的总分相加，使其看起来像这样

games day

到目前为止，我已经在 dplyr 中使用过这段代码 games_day %>% group_by(team_id) %>% summarize(total_points_for = sum(points_for))

这不会将它作为新变量添加到数据框中。对此的任何帮助将不胜感激

【问题讨论】：

用mutate()替换summarize()
嗨 b1lly_the_kid！欢迎来到堆栈溢出！请查看以下内容并相应更新您的帖子：How to make a great R reproducible example

标签： r dplyr

【解决方案1】：

试试这个：

library(tidyverse)
#Data
df <- structure(list(team_id = c("Red", "Blue", "Yellow", "Red", "Blue", 
"Yellow"), date = c("18/01/20", "18/01/20", "19/01/20", "19/01/20", 
"20/01/20", "20/01/20"), points_for = c(16L, 12L, 10L, 9L, 17L, 
13L), points_against = c(12L, 16L, 9L, 10L, 13L, 17L)), class = "data.frame", row.names = c(NA, 
-6L))

#Code
df %>% group_by(team_id) %>% mutate(total_points_for=sum(points_for,na.rm=T),
                                    total_points_against=sum(points_against,na.rm=T))

# A tibble: 6 x 6
# Groups:   team_id [3]
  team_id date     points_for points_against total_points_for total_points_against
  <chr>   <chr>         <int>          <int>            <int>                <int>
1 Red     18/01/20         16             12               25                   22
2 Blue    18/01/20         12             16               29                   29
3 Yellow  19/01/20         10              9               23                   26
4 Red     19/01/20          9             10               25                   22
5 Blue    20/01/20         17             13               29                   29
6 Yellow  20/01/20         13             17               23                   26

【讨论】：

【解决方案2】：

使用transform + ave 的基本 R 选项

transform(df,
  total_points_for = ave(points_for, team_id, FUN = sum),
  total_points_against = ave(points_against, team_id, FUN = sum)
)

【讨论】：