CODEWITHSUNDEEP
rif-statement
Gavia_immer
Gavia_immer

Reputation: 67

Nested ifelse statement with multiple selection criteria

YDST Year
0 2020
1 2020
2 2020
3 2020
4 2020
5 2020
6 2020
7 2020
8 2020
9 2020
10 2020
0 2021
1 2021
2 2021
3 2021
4 2021
5 2021
6 2021
7 2021
8 2021
9 2021
10 2021

I have a data frame ('df') where I want to create a new column ('Students') where 'ns' indicates no students and 's' indicates students. However where 'ns' and 's' occur differs between years based on 'YDST'. For instance, in 2020 'ns' should be indicated from 0-3 and 9-10. In 2021, 'ns' should be indicated from '1-4', '6-7', and '9-10'.

How can I write a nested ifelse statement to not only account for 'Year', but also the different 'YDST' selection criteria between years?

Thank you!

Upvotes: 0

Views: 52

Answers (2)

Ronak Shah
Ronak Shah

Reputation: 388797

You can use a ifelse statement to check for the conditions and assign value 'ns' or 's'.

transform(df, students = ifelse(Year == 2020 & YDST %in% c(0:3, 9, 10) | 
                           Year == 2021 & YDST %in% c(1:4, 6:7, 9:10), 'ns','s'))

#   YDST Year students
#1     0 2020       ns
#2     1 2020       ns
#3     2 2020       ns
#4     3 2020       ns
#5     4 2020        s
#6     5 2020        s
#7     6 2020        s
#8     7 2020        s
#9     8 2020        s
#10    9 2020       ns
#11   10 2020       ns
#...
#...

data

df <- structure(list(YDST = c(0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 
10L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L), Year = c(2020L, 
2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 
2020L, 2021L, 2021L, 2021L, 2021L, 2021L, 2021L, 2021L, 2021L, 
2021L, 2021L, 2021L)), row.names = c(NA, -22L), class = "data.frame")

Upvotes: 1

akrun
akrun

Reputation: 886928

We can create a key/value dataset and do a join

library(dplyr)
keyval <- data.frame(Year = rep(c(2020, 2021), c(5, 8)) 
        val = c(0:3, 9:10, 1:4, 6:7, 9:10))
left_join(df, keyval) %>%
       mutate(Students = case_when(YDST %in% val ~ 'ns', TRUE ~ 's'), val = NULL)

Upvotes: 0

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