Possible Duplicate:
Basic lag in R vector/dataframe
Trying to lag a variable in R but it isn't working.
x<-1:10
y=lag(x,1)
xy=cbind(x,y)
View(xy)
x y
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
6 6 6
7 7 7
8 8 8
9 9 9
10 10 10
I am still not getting the lag. What am I doing wrong? Also is there a quicker way to combine to vectors/matrices without using cbind/rbind? For example
x=0:10
y=20:30
newxy=[x,y]
Thank you!
lag() expects a time series. (In R, class "ts" is the basic time-series class, used to represent data sampled at equispaced points in time. For more see ?ts.) So you can either convert x to a time-series, as demonstrated here, or make use one of the approaches suggested in another answer.
x <- as.ts(1:10)
y <- lag(x,1)
xy <- cbind(x,y)
xy
#Time Series:
#Start = 0
#End = 10
#Frequency = 1
# x y
# 0 NA 1
# 1 1 2
# 2 2 3
# 3 3 4
# 4 4 5
# 5 5 6
# 6 6 7
# 7 7 8
# 8 8 9
# 9 9 10
#10 10 NA
For the second part:
newxy=matrix(c(x,y),ncol=2)
> newxy
[,1] [,2]
[1,] 0 20
[2,] 1 21
[3,] 2 22
[4,] 3 23
[5,] 4 24
[6,] 5 25
[7,] 6 26
[8,] 7 27
[9,] 8 28
[10,] 9 29
[11,] 10 30
embed is a useful function here, especially if you don't want to convert to a ts object.
x <- 1:10
embed(x,2)
[,1] [,2]
[1,] 2 1
[2,] 3 2
[3,] 4 3
[4,] 5 4
[5,] 6 5
[6,] 7 6
[7,] 8 7
[8,] 9 8
[9,] 10 9
