[R] reshape help

[Chuck Cleland]

juli pausas wrote:
> Hi,
> I'm trying to use reshape but I cannot quite understand how it works.
> Could somebody help me on this? Example, my data is something like:
> 
> mydat <- data.frame(tree= 1:10, serra=rep(1:2, c(5,5)), bt01= 101:110,
> bt02= 201:210, bt03= 301:310,  mm01= 9101:9110, mm02= 9201:9210, mm03=
> 9301:9310)
> 
>> mydat
>    tree serra bt01 bt02 bt03 mm01 mm02 mm03
> 1     1     1  101  201  301  9101  9201  9301
> 2     2     1  102  202  302  9102  9202  9302
> 3     3     1  103  203  303  9103  9203  9303
> 4     4     1  104  204  304  9104  9204  9304
> 5     5     1  105  205  305  9105  9205  9305
> 6     6     2  106  206  306  9106  9206  9306
> 7     7     2  107  207  307  9107  9207  9307
> 8     8     2  108  208  308  9108  9208  9308
> 9     9     2  109  209  309  9109  9209  9309
> 10   10     2  110  210  310  9110  9210  9310
> 
> that is, in the "wide form" with 2 constant variables (tree, serra)
> and 6 variables that correspond to two variables (bt mm) measured in 3
> years 01, 02, 03
> 
> I would like to reshaped the data to the long format as follows:
> 
>   tree serra   YEAR   bt   mm
>      1     1    2001   101   9101
>      2     1    2001   102   9102
>      3     1    2001   103   9103
>      4     1    2001   104   9104
>      5     1    2001   105   9105
>      6     2    2001   106   9106
>      7     2    2001   107   9107
>      8     2    2001   108   9108
>      9     2    2001   109   9109
>     10     2    2001   110   9110
>      1     1    2002   201   9201
>      2     1    2002   202   9202
>      3     1    2002   203   9203
>      4     1    2002   204   9204
>      5     1    2002   205   9205
>      6     2    2002   206   9206
>      7     2    2002   207   9207
>      8     2    2002   208   9208
>      9     2    2002   209   9209
>     10     2    2002   210   9210
>      1     1    2003   301   9301
>      2     1    2003   302   9302
>      3     1    2003   303   9303
>      4     1    2003   304   9304
>      5     1    2003   305   9305
>      6     2    2003   306   9306
>      7     2    2003   307   9307
>      8     2    2003   308   9308
>      9     2    2003   309   9309
>     10     2    2003   310   9310
> 
> I would appreciate if somebody let me know how could I do this with reshape

reshape(mydat, varying = list(c("bt01","bt02","bt03"),
                              c("mm01","mm02","mm03")),
               v.names=c("bt","mm"),
               timevar = "YEAR",
               times = c(2001, 2002, 2003),
               idvar = "tree",
               direction = "long")

        tree serra YEAR  bt   mm
1.2001     1     1 2001 101 9101
2.2001     2     1 2001 102 9102
3.2001     3     1 2001 103 9103
4.2001     4     1 2001 104 9104
5.2001     5     1 2001 105 9105
6.2001     6     2 2001 106 9106
7.2001     7     2 2001 107 9107
8.2001     8     2 2001 108 9108
9.2001     9     2 2001 109 9109
10.2001   10     2 2001 110 9110
1.2002     1     1 2002 201 9201
2.2002     2     1 2002 202 9202
3.2002     3     1 2002 203 9203
4.2002     4     1 2002 204 9204
5.2002     5     1 2002 205 9205
6.2002     6     2 2002 206 9206
7.2002     7     2 2002 207 9207
8.2002     8     2 2002 208 9208
9.2002     9     2 2002 209 9209
10.2002   10     2 2002 210 9210
1.2003     1     1 2003 301 9301
2.2003     2     1 2003 302 9302
3.2003     3     1 2003 303 9303
4.2003     4     1 2003 304 9304
5.2003     5     1 2003 305 9305
6.2003     6     2 2003 306 9306
7.2003     7     2 2003 307 9307
8.2003     8     2 2003 308 9308
9.2003     9     2 2003 309 9309
10.2003   10     2 2003 310 9310

> Thanks in advance
> 
> Juli 

-- 
Chuck Cleland, Ph.D.
NDRI, Inc.
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New York, NY 10010
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