根据 R 中另一列中的顺序创建列

Question

我有一个数据框，它的版本更长：

council_name <- c("Southwark", "Southwark", "Southwark", "Lambeth", "Lambeth", "Lambeth", "Yorkshire", "Yorkshire", "Yorkshire")
quarter <- c("2006 Q1", "2006 Q2", "2006 Q3", "2006 Q1", "2006 Q2", "2006 Q3","2006 Q1", "2006 Q2", "2006 Q3")
treat <- c(1, 0, 1, 0, 0, 1, 0, 0, 0)
df.desired <- as.data.frame(c(council_name, as.yearqtr(quarter), treat, df, first.treatment))

我想要的是“council_name”的每个值在“治疗”第一次为 1 时具有“季度”值的列。如果特定 council_name.

的“治疗”从不为 1，则为“0”

这会像这样：

library(zoo)
council_name <- c("Southwark", "Southwark", "Southwark", "Lambeth", "Lambeth", "Lambeth", "Yorkshire", "Yorkshire", "Yorkshire")
quarter <- c("2006 Q1", "2006 Q2", "2006 Q3", "2006 Q1", "2006 Q2", "2006 Q3","2006 Q1", "2006 Q2", "2006 Q3")
treat <- c(1, 0, 1, 0, 0, 1, 0, 0, 0)
first.treatment <- c("2006 Q1", "2006 Q3", 0)
df.desired <- as.data.frame <- c(council_name, as.yearqtr(quarter), treat, df, first.treatment)

我用 group_by 和排序尝试了不同的东西，但我从来没有完全明白我要找的东西。

我尝试过的一个例子是：

merged2%>%
  group_by(council_name, year_qtr)%>%
  arrange(year_qtr)%>%
  mutate(first.treatment = by(year_qtr, head, 1))

但得到了：

Error: Problem with `mutate()` input `first.treatment`. x unique() applies only to vectors ℹ Input `first.treatment` is `by(year_qtr, head, 1)`. ℹ The error occured in group 1: council_name = "Adur", year_qtr = 2006 Q2.

非常感谢！

Answer 1

我确实对示例数据做了一些调整，但我非常希望，这就是你的意思。我不喜欢 return 字符串或 0 的想法。应该始终 return 相同的数据类型。这就是为什么我的回答 return 要么 quarter 要么 NA。如果您坚持 returning 0 可以使用 is.na.

轻松“修复”

council_name <- c("Southwark", "Southwark", "Southwark", "Lambeth", "Lambeth", "Lambeth", "Yorkshire", "Yorkshire", "Yorkshire")
quarter <- c("2006 Q1", "2006 Q2", "2006 Q3", "2006 Q1", "2006 Q2", "2006 Q3","2006 Q1", "2006 Q2", "2006 Q3")
treat <- c(1, 0, 1, 0, 0, 1, 0, 0, 0)
df <- data.frame(council_name, quarter, treat)

treat.one <- function(d){
  line <- which(d$treat == 1)[1]
  return(d$quarter[line])
}

by(df, council_name, treat.one)

这需要

  council_name quarter treat
1    Southwark 2006 Q1     1
2    Southwark 2006 Q2     0
3    Southwark 2006 Q3     1
4      Lambeth 2006 Q1     0
5      Lambeth 2006 Q2     0
6      Lambeth 2006 Q3     1
7    Yorkshire 2006 Q1     0
8    Yorkshire 2006 Q2     0
9    Yorkshire 2006 Q3     0

和returns

> by(df, council_name, treat.one)
council_name: Lambeth
[1] "2006 Q3"
----------------------------------------- 
council_name: Southwark
[1] "2006 Q1"
----------------------------------------- 
council_name: Yorkshire
[1] NA

Answer 2

当使用 group_by 时，mutate 调用将依次考虑所有组中的每个变量。

因此，你可以这样写：

tibble(council_name, year_qtr=as.yearqtr(quarter), treat) %>% 
  group_by(council_name) %>% 
  arrange(year_qtr) %>% 
  mutate(first_treatment = year_qtr[treat==1][1]) %>% 
  arrange(council_name, year_qtr)

或

tibble(council_name, year_qtr=as.yearqtr(quarter), treat) %>% 
  group_by(council_name) %>% 
  arrange(year_qtr) %>% 
  summarise(first_treatment = year_qtr[treat==1][1])

对于每个组，这会要求 year_qtr 列，其中 treat==1，并获取结果向量的第一个值。这就是为什么事先排序很重要 (arrange)。

根据 R 中另一列中的顺序创建列

Create column based on ordering in another column in R

r

dataframe

zoo

dplyr

tidyverse