Applying a function to switch the position of rows repeatedly-CodePudding

I am currently working on a super long dataframe in R that looks like this

Year	Value
1912	0.5
1912	0.6
1913	0.2
1913	0.3
1914	1.4
1915	1.2

And I need to switch the position every two rows so that it looks like this

Year	Value
1912	0.6
1912	0.5
1913	0.3
1913	0.2
1914	1.2
1915	1.4

I feel so confused about if there is anything I can do to achieve that or I need to write the function by myself

CodePudding user response：

We can group by Year and reverse the 'Value' column

library(dplyr)
df1 %>%
    group_by(Year) %>%
    mutate(Value = rev(Value)) %>%
    ungroup

data

df1 <- structure(list(Year = c(1912L, 1912L, 1913L, 1913L, 1914L, 1915L
), Value = c(0.5, 0.6, 0.2, 0.3, 1.4, 1.2)), 
class = "data.frame", row.names = c(NA, 
-6L))