CODEWITHSUNDEEP
r
ian
ian

Reputation: 27

trying to subtract a vector from a time series in the correct order

I have a time series from 1951 to 2012. Part below

       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
1951                                     15.50 18.74 22.75 25.90 25.43 27.61
1952 27.60 27.72 27.63 24.38 20.34 17.74 17.90 20.57 23.13 25.60 26.41 26.98
1953 25.80 26.19 24.99 23.23 19.59 15.78 14.85 18.97 20.44 25.78 26.65 27.00
1954 26.25 26.97 25.33 23.16 20.47 15.47 15.64 18.33 22.71 26.71 25.77 25.94

I also got vector of the means of all the Jans, Feb, etc, below

 [1] 27.80410 27.24500 26.14211 23.76737 20.19474 16.87368 16.71846 19.28359 22.74385
[10] 25.22513 26.50128 27.21410

I need to subtract the mean of January from all the Januaries, the same for February etc.

But if I do a simple subtract I will get January subtracting from Julys etc

The time series is a time series and the mean is a vector.

Can you tell me how to get past this and the whole process is part of a loop.

Upvotes: 1

Views: 89

Answers (1)

akrun
akrun

Reputation: 887158

We need to use the cycle function to index the time series

ts1-v1[cycle(ts1)]
#       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
#1951                                     -1.21 -0.54  0.01  0.67 -1.07  0.41
#1952 -0.20  0.48  1.49  0.62  0.15  0.87  1.19  1.29  0.39  0.37 -0.09 -0.22
#1953 -2.00 -1.05 -1.15 -0.53 -0.60 -1.09 -1.86 -0.31 -2.30  0.55  0.15 -0.20
#1954 -1.55 -0.27 -0.81 -0.60  0.28 -1.40 -1.07 -0.95 -0.03  1.48 -0.73 -1.26

data

ts1 <- structure(c(15.5, 18.74, 22.75, 25.9, 25.43, 27.61, 27.6, 27.72, 
27.63, 24.38, 20.34, 17.74, 17.9, 20.57, 23.13, 25.6, 26.41, 
26.98, 25.8, 26.19, 24.99, 23.23, 19.59, 15.78, 14.85, 18.97, 
20.44, 25.78, 26.65, 27, 26.25, 26.97, 25.33, 23.16, 20.47, 15.47, 
15.64, 18.33, 22.71, 26.71, 25.77, 25.94), .Tsp = c(1951.5, 1954.91666666667, 
 12), class = "ts")


v1 <- c(27.80, 27.24, 26.14, 23.76, 20.19, 16.87, 16.71, 19.28, 22.74, 25.23,
 26.5, 27.2)

Upvotes: 1

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