根据先前的历史记录创建一个新变量 [英] Creating a new variable based on prior history

问题描述

例如，我有需要根据以前的历史记录创建变量的数据

I have data where I need to create a variable based on prior history, for example

 created<- c(2009,2010,2010,2011, 2012, 2011)
 person <- c(A, A, A, A, B, B)
 location<- c('London','Geneva', 'London', 'New York', 'London', 'London')
 df <- data.frame (created, person, location)

我想创建一个名为"existing"的变量，该变量考虑到前几年的情况，并查看他/她是否住过该地方，如果该地方是旧的(并且他们住在那里，则给出的值为0).?

I want to create a variable called 'existing' that takes into account the prior years and sees if he/she has lived in that place and gives a value of 0 if the place is old(and they lived there. Any suggestions?

 library(dplyr) 
 df %>% group_by(person) %>% mutate (existing=0)

  existing<- c(1, 1, 0, 1, 0,1)

推荐答案

另一个 dplyr 选项可能是:

df %>%
 group_by(person, location) %>%
 mutate(existing = +(1:n() == 1))

  created person location existing
    <dbl> <fct>  <fct>       <int>
1    2009 A      London          1
2    2010 A      Geneva          1
3    2010 A      London          0
4    2011 A      New York        1
5    2012 B      London          1
6    2011 B      London          0

如果需要排序:

df %>%
 group_by(person, location) %>%
 arrange(created, .by_group = TRUE) %>%
 mutate(existing = +(1:n() == 1))

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