R中的and和or条件的多个ifelse

Question

I have a dataset and I want to create a multiple ifelse statement. I want to find out if this person/id lived in the big city (being london or paris) in the years 2011 and 2012. Any suggestions how I can get this with multiple ifelse?

 id<-  c(1,1,2,2,3)
 location <- c('london', 'paris', 'london', 'kathmanadu','newyork')
 year<- c(2011, 2010, 2012, 2011, 2010)
 df<- data.frame(location, year)
 df$bigcity<- ifelse(df$location=='london'| df$location=='paris' & 
 df$year==2011| df$year==2012, 1, 0)

Answer 1

I think by multiple ifelse you mean nested ifelse. if that is the case, here is a solution

df$bigcity <- ifelse(grepl("london|paris", df$location), ifelse(grepl("2011|2012", df$year), 1, 0), 0)

what I did here is, IF the first condition is true, place the second condition in TRUE parameter.

Answer 2

With data.table it comes out as:

library(data.table)
setDT(df)
df[,location := ifelse(location %in% c('paris','london') & year %in% c(2011,2012),1,0)]

   id   location year new_value
1:  1     london 2011         1
2:  1      paris 2010         0
3:  2     london 2012         1
4:  2 kathmanadu 2011         0
5:  3    newyork 2010         0

Answer 3

A dplyr solution using filter , since I think its much more readable than nested ifelse

 id<-  c(1,1,2,2,3)
 location <- c('london', 'paris', 'london', 'kathmanadu','newyork')
 year<- c(2011, 2010, 2012, 2011, 2010)
 df<- data.frame(id, location, year)

I want to find out if this person/id lived in the big city (being london or paris) in the years 2011 and 2012

library(dplyr)
df %>% 
  filter(location %in% c('london', 'paris')) %>%
  filter(year %in% c(2011, 2012))

#   id location year
#1  1   london 2011
#2  2   london 2012