I have a dataset like that

I want to add a column with season time like this:

How can I do a code in R that automatically add a column where all January, February and December are Winter, all March, April and May are Spring and so on.

Thanks a lot for helping

season <- c(data, Spring = "March", Spring = "April")

CodePudding user response：

We can create a keyvalue dataset and do a join

library(dplyr)
keydat <- tibble(Month = month.name, 
   Season = rep(c("Winter", "Spring", "Summer", "Fall", "Winter"), 
      c(2, 3, 3, 3, 1)))
df1 <- left_join(df1, keydat)

-output

df1
      Month Year Region Season
1   January 2019     NY Winter
2  February 2019     NY Winter
3     March 2019     NY Spring
4 September 2019     NY   Fall

data

df1 <- structure(list(Month = c("January", "February", "March", "September"
), Year = c(2019L, 2019L, 2019L, 2019L), Region = c("NY", "NY", 
"NY", "NY")), class = "data.frame", row.names = c(NA, -4L))

CodePudding user response：

In base R you could do:

df1$Season <- c('Winter', 'Spring', 'Summer', 'Fall')[
  1   (match(df1$Month, month.name) %/% 3) %% 4]

Which results in:

df1
#>       Month Year Region Season
#> 1   January 2019     NY Winter
#> 2  February 2019     NY Winter
#> 3     March 2019     NY Spring
#> 4 September 2019     NY   Fall

(Using akrun's reproducible data)