[R] Changing the order of months within a year

Tue Feb 12 15:09:46 CET 2013

Hi,

You could try:
dat1<- read.table(text="
        site          date year precipitation temp_max temp_min
1  castlepeak Jan-71 1971    26.2903226 38.29032 18.06452
2  castlepeak Feb-71 1971    9.1071429 39.60714 17.50000
3  castlepeak Mar-71 1971    36.3548387 38.87097 17.77419
4  castlepeak Apr-71 1971    14.8333333 44.06667 22.56667
5  castlepeak May-71 1971    11.0967742 47.87097 29.22581
6  castlepeak Jun-71 1971    7.9000000 62.20000 34.16667
7  castlepeak Jul-71 1971    0.4516129 75.45161 44.93548
8  castlepeak Aug-71 1971    1.1612903 76.54839 45.96774
9  castlepeak Sep-71 1971    0.9333333 68.30000 36.86667
10 castlepeak Oct-71 1971    10.1612903 56.22581 31.74194
11 castlepeak Nov-71 1971    58.1000000 43.13333 28.43333
12 castlepeak Dec-71 1971    56.0645161 30.87097 16.29032
13 castlepeak Jan-72 1972    16.7741935 33.90323 15.41935
14 castlepeak Feb-72 1972    30.4137931 37.62069 19.82759
15 castlepeak Mar-72 1972    12.5161290 46.45161 24.06452
16 castlepeak Apr-72 1972    20.9333333 41.23333 22.10000
17 castlepeak May-72 1972    3.3870968 53.06452 28.77419
18 castlepeak Jun-72 1972    3.7666667 65.60000 37.93333
19 castlepeak Jul-72 1972    0.0000000 74.25806 43.45161
20 castlepeak Aug-72 1972    0.2258065 73.35484 43.03226
21 castlepeak Sep-72 1972    5.4000000 65.66667 37.90000
22 castlepeak Oct-72 1972    5.1612903 51.00000 27.38710
23 castlepeak Nov-72 1972    23.0666667 40.10000 23.43333
24 castlepeak Dec-72 1972    50.7096774 27.00000 10.16129
",sep="",header=TRUE,stringsAsFactors=FALSE)
library(zoo)
vec1<- c("Sep","Oct","Nov","Dec","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug")
 dat2<-do.call(rbind,lapply(split(dat1,dat1$year), function(x)x[match(vec1,format(as.yearmon(x$date,"%b-%y"),"%b")),]))
 row.names(dat2)<- 1:nrow(dat2)

dat2
#         site   date year precipitation temp_max temp_min
#1  castlepeak Sep-71 1971     0.9333333 68.30000 36.86667
#2  castlepeak Oct-71 1971    10.1612903 56.22581 31.74194
#3  castlepeak Nov-71 1971    58.1000000 43.13333 28.43333
#4  castlepeak Dec-71 1971    56.0645161 30.87097 16.29032
#5  castlepeak Jan-71 1971    26.2903226 38.29032 18.06452
#6  castlepeak Feb-71 1971     9.1071429 39.60714 17.50000
#7  castlepeak Mar-71 1971    36.3548387 38.87097 17.77419
#8  castlepeak Apr-71 1971    14.8333333 44.06667 22.56667
#9  castlepeak May-71 1971    11.0967742 47.87097 29.22581
#10 castlepeak Jun-71 1971     7.9000000 62.20000 34.16667
#11 castlepeak Jul-71 1971     0.4516129 75.45161 44.93548
#12 castlepeak Aug-71 1971     1.1612903 76.54839 45.96774
#13 castlepeak Sep-72 1972     5.4000000 65.66667 37.90000
#14 castlepeak Oct-72 1972     5.1612903 51.00000 27.38710
#15 castlepeak Nov-72 1972    23.0666667 40.10000 23.43333
#16 castlepeak Dec-72 1972    50.7096774 27.00000 10.16129
#17 castlepeak Jan-72 1972    16.7741935 33.90323 15.41935
#18 castlepeak Feb-72 1972    30.4137931 37.62069 19.82759
#19 castlepeak Mar-72 1972    12.5161290 46.45161 24.06452
#20 castlepeak Apr-72 1972    20.9333333 41.23333 22.10000
#21 castlepeak May-72 1972     3.3870968 53.06452 28.77419
#22 castlepeak Jun-72 1972     3.7666667 65.60000 37.93333
#23 castlepeak Jul-72 1972     0.0000000 74.25806 43.45161
#24 castlepeak Aug-72 1972     0.2258065 73.35484 43.03226
A.K.

----- Original Message -----
From: nick pardikes <npardikes at hotmail.com>
To: "r-help at R-project.org" <r-help at r-project.org>
Cc: 
Sent: Tuesday, February 12, 2013 1:09 AM
Subject: [R] Changing the order of months within a year

I have data that looks like below and I would like to re-order the values within the "date" column. I would like to have each year organized like so:

Sep-71
Oct-71
Nov-71
Dec-71
Jan-71
Feb-71
Mar-71
Apr-71
May-71
Jun-71
Jul-71
Aug-71
Sep-72
Oct-72
etc...

Is there any way I can order the column in my own fashion and just move Sep-Dec to the beginning of each year? I am planning on doing some time series analysis with this data and think that the order of months is very important for the time series. I appreciate any suggestions and thank you in advance. 

        site           date year precipitation temp_max temp_min
1  castlepeak Jan-71 1971    26.2903226 38.29032 18.06452
2  castlepeak Feb-71 1971     9.1071429 39.60714 17.50000
3  castlepeak Mar-71 1971    36.3548387 38.87097 17.77419
4  castlepeak Apr-71 1971    14.8333333 44.06667 22.56667
5  castlepeak May-71 1971    11.0967742 47.87097 29.22581
6  castlepeak Jun-71 1971     7.9000000 62.20000 34.16667
7  castlepeak Jul-71 1971     0.4516129 75.45161 44.93548
8  castlepeak Aug-71 1971     1.1612903 76.54839 45.96774
9  castlepeak Sep-71 1971     0.9333333 68.30000 36.86667
10 castlepeak Oct-71 1971    10.1612903 56.22581 31.74194
11 castlepeak Nov-71 1971    58.1000000 43.13333 28.43333
12 castlepeak Dec-71 1971    56.0645161 30.87097 16.29032
13 castlepeak Jan-72 1972    16.7741935 33.90323 15.41935
14 castlepeak Feb-72 1972    30.4137931 37.62069 19.82759
15 castlepeak Mar-72 1972    12.5161290 46.45161 24.06452
16 castlepeak Apr-72 1972    20.9333333 41.23333 22.10000
17 castlepeak May-72 1972     3.3870968 53.06452 28.77419
18 castlepeak Jun-72 1972     3.7666667 65.60000 37.93333
19 castlepeak Jul-72 1972     0.0000000 74.25806 43.45161
20 castlepeak Aug-72 1972     0.2258065 73.35484 43.03226
21 castlepeak Sep-72 1972     5.4000000 65.66667 37.90000
22 castlepeak Oct-72 1972     5.1612903 51.00000 27.38710
23 castlepeak Nov-72 1972    23.0666667 40.10000 23.43333
24 castlepeak Dec-72 1972    50.7096774 27.00000 10.16129

Nick Pardikes
PhD Student
Program in Ecology, Evolution and Conservation Biology
University of Nevada, Reno
303-550-1072
http://wolfweb.unr.edu/homepage/npardikes/MySite/Welcome.html

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