Question

我想根据前一列创建一个名为age的新列，并按功能分组。数据集如下：

tid<- c(1,2,3,4, 1,2,3,4,1,2,3,4)
active<- c(0,1,0,4, 0,0,0,1,0,0,1,0)
person<- c('John', 'John','John', 'John', 'Emma', 'Emma','Emma','Emma', 'Edward', 'Edward', 'Edward', 'Edward')
df<- data.frame(tid, active, person)

我想创建一个年龄，该年龄是在该人首次激活时从0开始的，即，active的值首次大于0，然后为下一条记录递增一个值。有什么建议么？

我期望输出如下：

 name     age 
 John     0
 John     0
 John     1
 John     2
 Emma     0
 Emma     0
 Emma     0
 Emma     0
 Edward   0
 Edward   0
 Edward   0
 Edward   1

Answer 1

这能为您解决吗？

library(dplyr)

df %>% 
  group_by(person) %>% 
  arrange(person, tid) %>%
  mutate(active_dummy = if_else(lag(cumsum(active)) > 0, 1, 0, 0),
         age = cumsum(active_dummy)) %>% 
  select(person, age)

给你

# A tibble: 12 x 2
# Groups:   person [3]
   person   age
   <chr>  <dbl>
 1 John      0.
 2 John      0.
 3 John      1.
 4 John      2.
 5 Emma      0.
 6 Emma      0.
 7 Emma      0.
 8 Emma      0.
 9 Edward    0.
10 Edward    0.
11 Edward    0.
12 Edward    1.

Answer 2

另一种可以解决问题的解决方案：

library(tidyverse)

age_counter = df %>% 
    arrange(tid) %>%
    group_by(person) %>% 
    filter(cumsum(active) > 0) %>% 
    mutate(age = row_number() - 1)

df %>% 
    left_join(age_counter) %>%
    replace_na(list(age = 0)) %>%
    select(person, age)

使用mutate和group by添加新列

2 个答案: