[R] reshape data.frame

[William Dunlap]

You can use the reshape() in core R (the stats package)

> reshape(a, timevar="year", idvar="name", direction="wide")
   name amount.1971 amount.1972 amount.1973 amount.1974
1     a           1           2           3           4
11    b          11          12          13          14
   amount.1975 amount.1976 amount.1977 amount.1978
1            5           6           7           8
11          15          16          17          18
   amount.1979 amount.1980 amount.1981 amount.1982
1            9          10          NA          NA
11          19          20          21          22
   amount.1983 amount.1984 amount.1985
1           NA          NA          NA
11          23          24          25

(Was naming the output columns "X.<year>" instead of "amount.<year>"
important?)

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Trevor Davies
> Sent: Friday, November 18, 2011 4:05 PM
> To: r-help at r-project.org
> Subject: [R] reshape data.frame
> 
> A late friday afternoon coding question.  I'm having a hard time thinking
> of the correct search terms for what I want to do.
> 
> If I have a df like this:
> 
>  a <-
> data.frame(name=c(rep('a',10),rep('b',15)),year=c(1971:1980,1971:1985),amount=1:25)
>    name year amount
> 1     a 1971      1
> 2     a 1972      2
> 3     a 1973      3
> 4     a 1974      4
> 5     a 1975      5
> 6     a 1976      6
> 7     a 1977      7
> 8     a 1978      8
> 9     a 1979      9
> 10    a 1980     10
> 11    b 1971     11
> 12    b 1972     12
> 13    b 1973     13
> 14    b 1974     14
> 15    b 1975     15
> 16    b 1976     16
> 17    b 1977     17
> 18    b 1978     18
> 19    b 1979     19
> 20    b 1980     20
> 21    b 1981     21
> 22    b 1982     22
> 23    b 1983     23
> 24    b 1984     24
> 25    b 1985     25
> 
> 
> and I'd like to reshape it so it is like this:
>  X.1971 X.1972 X.1973 X.1974 X.1975 X.1976 X.1977 X.1978 X.1979 X.1980
> X.1981
> a      1      2      3      4      5      6      7      8      9     10
> NA
> b     11     12     13     14     15     16     17     18     19     20
> 21
>   X.1982 X.1983 X.1984 X.1985
> a     NA     NA     NA     NA
> b     22     23     24     25
> 
> Thanks for the assist.
> 
> 	[[alternative HTML version deleted]]
> 
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