根据另一个单元格中的值操作组内的单元格答案

【问题标题】：Manipulating cells within a group based on value in another cell根据另一个单元格中的值操作组内的单元格
【发布时间】：2020-09-24 03:24:56
【问题描述】：

我有一个格式如下的data.frame：

CowId    Bacillus    Week
1234     1           Week1
1234     0           Week2
1234     0           Week3
1234     0           Week4

如果一头奶牛在第 1 周是芽孢杆菌阳性（是=1，否=0），那么我想将此列中的剩余值更改为 1，如下所示：

CowId    Bacillus    Week
1234     1           Week1
1234     1           Week2
1234     1           Week3
1234     1           Week4

我尝试了以下方法，但在确定第 1 周奶牛的感染状态后不确定如何进行：

dt %>%
    group_by(CowId) %>%
    mutate(Bacillus = ifelse(Week == "Week1" & Bacillus, 1,
                          ifelse(Week != "Week1" do something)

感谢任何 cmets/反馈。

【问题讨论】：

标签： r dplyr tidyverse

【解决方案1】：

使用any() 尝试这种方法并测试一周。我创建了虚拟数据来显示示例：

library(dplyr)
library(tidyr)
#Code
df %>% group_by(CowId) %>%
  mutate(Bacillus=ifelse(any(Bacillus[Week=='Week1']==1),1,0))

输出：

# A tibble: 8 x 3
# Groups:   CowId [2]
  CowId Bacillus Week 
  <dbl>    <dbl> <chr>
1  1234        1 Week1
2  1234        1 Week2
3  1234        1 Week3
4  1234        1 Week4
5  1235        0 Week1
6  1235        0 Week2
7  1235        0 Week3
8  1235        0 Week4

使用的一些数据：

#Data
df <- structure(list(CowId = c(1234, 1234, 1234, 1234, 1235, 1235, 
1235, 1235), Bacillus = c(1, 0, 0, 0, 0, 0, 0, 0), Week = c("Week1", 
"Week2", "Week3", "Week4", "Week1", "Week2", "Week3", "Week4"
)), row.names = c(NA, -8L), class = "data.frame")

【讨论】：

【解决方案2】：

在base R中，我们可以用'Bacillus'&'Week'创建一个逻辑向量，其值为'Week1'，子集'CowId'，检查它是否在'CowId'中，强制逻辑转二进制 (+)

df$Bacillus <- with(df, +(CowId %in% unique(CowId[as.logical(Bacillus) &
           Week == 'Week1'])))
df$Bacillus
#[1] 1 1 1 1 0 0 0 0

数据

df <- structure(list(CowId = c(1234, 1234, 1234, 1234, 1235, 1235, 
1235, 1235), Bacillus = c(1, 0, 0, 0, 0, 0, 0, 0), Week = c("Week1", 
"Week2", "Week3", "Week4", "Week1", "Week2", "Week3", "Week4"
)), row.names = c(NA, -8L), class = "data.frame")

【讨论】：