[R] reshape data.frame

[David Winsemius]

On Nov 18, 2011, at 7:04 PM, Trevor Davies wrote:

> 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

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