英文:
Adding values by row and have them apply to a single row variable while preserving other variables and rows
问题
这是你要的代码部分的翻译：
我有一个看起来像这样的数据框，
df <- data.frame(num1 = c('a','b','c','d')
,num2 = c(1,2,3,4)
,num3 = c(5,6,7,8)
,num4 = c('x','y','b','d'))
我想要的输出是从
num1 num2 num3 num4
a 1 5 x
b 2 6 y
c 3 7 b
d 4 8 d
到
num1 num2 num3 num4
a 10 26 x
b 2 6 y
c 3 7 b
d 4 8 d
这里是一个可以实现这一结果的示例
df <- data.frame(num1 = c('a', 'b', 'c', 'd'),
num2 = c(1, 2, 3, 4),
num3 = c(5, 6, 7, 8),
num4 = c('x', 'y', 'b', 'd'))
sum_summarised <- df %>%
filter(grepl('a|b|c', num1)) %>%
summarise(num2 = sum(num2), num3 = sum(num3))
df <- df %>%
mutate(num2 = if_else(num1 == 'a', sum_summarised$num2, num2))
df <- df %>%
mutate(num3 = if_else(num1 == 'a', sum_summarised$num3, num3))
基本上是对num2/num3列求和，并将求和结果应用于a行，同时保留变量b、c和d以及num4列的原始行值。最好使用dplyr - 我尝试过各种`group_by`、`slice`和`filter`的变种组合，但都无济于事。对于我面临的这个独特问题，任何帮助都将不胜感激。谢谢！<details><summary>英文:</summary>I have a dataframe that looks like,
df <- data.frame(num1 = c('a','b','c','d')
,num2 = c(1,2,3,4)
,num3 = c(5,6,7,8)
,num4 = c('x','y','b','d'))
And would like the out put to go from
num1 num2 num3 num4
a 1 5 x
b 2 6 y
c 3 7 b
d 4 8 d
To
num1 num2 num3 num4
a 10 26 x
b 2 6 y
c 3 7 b
d 4 8 d
Here is a sample that achieves the result in my own solution
df <- data.frame(num1 = c('a', 'b', 'c', 'd'),
num2 = c(1, 2, 3, 4),
num3 = c(5, 6, 7, 8),
num4 = c('x', 'y', 'b', 'd'))
sum_summarised <- df %>%
filter(grepl('a|b|c',num1)) %>%
summarise(num2 = sum(num2), num3 = sum(num3))
df <- df %>%
mutate(num2 = if_else(num1 == 'a',sum_summarised$num2,num2))
df <- df %>%
mutate(num3 = if_else(num1 == 'a',sum_summarised$num3,num3))
Essentially summing num2/num3 columns and applying the sum to row a variable while preserving original row values for variables b,c, and d and num 4 column values.Preference would be to use dplyr - I have tried variants of `group_by` and `slice` and `filter` combinations to no avail. Any help would be greatly appreciated in this unique problem I have faced. Thank you!</details># 答案1**得分**: 2由于您偏好使用 `dplyr`，我们可以使用 `across` 和 `if_else`：```Rlibrary(dplyr)df |>mutate(across(num2:num3, ~ if_else(num1 == "a", sum(.), .)))
输出：
num1 num2 num3 num41 a 10 26 x2 b 2 6 y3 c 3 7 b4 d 4 8 d
更新 如果我只想对 a、b 和 c 求和，而不是全部，而且只应用于 a 呢?：
library(dplyr)df |>mutate(across(num2:num3, ~ if_else(num1 == "a", sum(.[num1 %in% c("a", "b", "c")]), .)))
输出：
num1 num2 num3 num41 a 6 18 x2 b 2 6 y3 c 3 7 b4 d 4 8 d
英文:
Since you have a preference for dplyr, we could use across and if_else:
library(dplyr)df |>mutate(across(num2:num3, ~ if_else(num1 == "a", sum(.), .)))
Output:
num1 num2 num3 num41 a 10 26 x2 b 2 6 y3 c 3 7 b4 d 4 8 d
Update if i wanted to to just sum a, b, and c? not all? and apply to a?:
library(dplyr)df |>mutate(across(num2:num3, ~ if_else(num1 == "a", sum(.[num1 %in% c("a", "b", "c")]), .)))
Output:
num1 num2 num3 num41 a 6 18 x2 b 2 6 y3 c 3 7 b4 d 4 8 d
答案2
得分: 2
另一种方法是使用 rows_update()。这种方法稍微冗长一些，但如果我们想要构建更复杂的操作，我会说它是值得的。下面我们调用 rows_update()，在其中我们使用 summarise() 首先定义我们想要按 id 列进行连接的列，然后使用 across() 更新要更新的列，其他列将保持不变。
library(dplyr)df %>%rows_update(df %>%summarise(num1 = "a",across(num2:num3, sum)),by = "num1")
我们还可以在我们的 tibble 内执行更复杂的操作，例如，如果我们不想对 c 列进行求和，我们可以使用 filter()：
df %>%rows_update(df %>%filter(num1 != "c") %>%summarise(num1 = "a",across(num2:num3, sum)),by = "num1")
OP 的数据：
df <- data.frame(num1 = c('a','b','c','d'),num2 = c(1,2,3,4),num3 = c(5,6,7,8),num4 = c('x','y','b','d'))
2023-03-03 由 reprex package 创建
英文:
Another approach is to use rows_update(). This is a bit more verbose, but I'd say it pays of if we want to construct more complex operations. Below we call rows_update() and inside we use summarise() first defining the id column we want to join by and then the columns we want to update with `across(), everything else will be untouched.
library(dplyr)df %>%rows_update(df %>%summarise(num1 = "a",across(num2:num3, sum)),by = "num1")#> num1 num2 num3 num4#> 1 a 10 26 x#> 2 b 2 6 y#> 3 c 3 7 b#> 4 d 4 8 d
We can also perform more complex operations inside our tibble for example if we don't want to sum-up c we can filter():
df %>%rows_update(df %>%filter(num1 != "c") %>%summarise(num1 = "a",across(num2:num3, sum)),by = "num1")#> num1 num2 num3 num4#> 1 a 7 19 x#> 2 b 2 6 y#> 3 c 3 7 b#> 4 d 4 8 d
Data from OP
df <- data.frame(num1 = c('a','b','c','d'),num2 = c(1,2,3,4),num3 = c(5,6,7,8),num4 = c('x','y','b','d'))
<sup>Created on 2023-03-03 by the reprex package (v2.0.1)</sup>
答案3
得分: 0
以下是翻译好的代码部分：
# 可能的一种方法是使用'dplyr'包中的`transmute()`函数：library(tidyverse)df %>%transmute(num1,num2 = c(sum(num2), num2[-1]),num3 = c(sum(num3), num3[-1]),num4)
请注意，这是代码的翻译部分，没有其他内容。
英文:
One way could be using transmute() from 'dplyr' package:
library(tidyverse)df %>%transmute(num1,num2 = c(sum(num2), num2[-1]),num3 = c(sum(num3), num3[-1]),num4)num1 num2 num3 num41 a 10 26 x2 b 2 6 y3 c 3 7 b4 d 4 8 d
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