Question

i have a data frame like this

A B value
1 1 0.123
2 1 0.213
3 1 0.543
1 2 0.313
2 2 0.123
3 2 0.412

what i want to do is to create a function that shift this data frame by a value. for example:

if the value of shifting is 1 the data frame will become:

A B value
3 2 0.412
1 1 0.123
2 1 0.213
3 1 0.543
1 2 0.313
2 2 0.123

etc…

the function should be like this.

shift<-function(dataframe,shiftvalue)

is there any simple way to do this in R without entering in a lot of loops??

Answer 1

You can do it many ways, but one way is to use head and tail:

df <- data.frame(a=1:10, b = 11:20)

shift <- function(d, k) rbind( tail(d,k), head(d,-k), deparse.level = 0 )


> shift(df,3)
    a  b
4   4 14
5   5 15
6   6 16
7   7 17
8   8 18
9   9 19
10 10 20
1   1 11
2   2 12
3   3 13