I have three columns:
> df
ID city destination
1 1 London 3
2 2 Paris 2
3 3 New York 5
4 4 Tokyo 4
5 5 Beijing 1
I need to add a 4th column that takes whatever the value is in the Destination column, finds it in the ID column, then pulls out the associated string in the City column - so that it would look like this
ID city destination city_destination
1 1 London 3 New York
2 2 Paris 2 Paris
3 3 New York 5 Beijing
4 4 Tokyo 4 Tokyo
5 5 Beijing 1 London
I know how to look up a value in the ID column and return something:
df_destination <- df %>%
mutate(city_destination = ifelse(grepl("3", ID), 1, 0))
But I cannot figure out how to
- Go through each value in Column A and look for it in Column B
- Return a string from Column C
Help on this would be much appreciated!
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