[R-sig-eco] Understanding cbind

[Mario José Marques]

Hi Manuel,

when you use cbind(finaldf[, 3:22], cbind function waiting that you gave 
second data to bind with first. How you use only one data, its result like:

DEV <- finaldf[, 3:22]

with the same structure of data frame finaldf.

When you use cbind(finaldf$oc1, finaldf$oc2,... you bind a vector of 
number into columns. Its like:

v1 <- 0,0,0,1,1,1
v2 <- 1,1,1,0,0,0
...

cbind(v1, v2, ...)

that result:

       [ ,1] [ ,1]
[1, ] 0     1
[2, ] 0     1
[3, ] 0     1
[4, ] 1     0
[5, ] 1     0
[6, ] 1     0

Regards,

MJ
...................................................
Mario José Marques
Master student in Ecology
Institute of Biology, Dept. Plant Biology, Ecology Lab.
State University of Campinas - UNICAMP
Campinas, São Paulo, Brazil

On 20/07/2012 13:13, Manuel Spínola wrote:
> Dear list members,
>
> I am using function cbind but I got 2 different results, one is a data
> frame and the other is a matrix and I would like to undertand why is the
> reason:
>
> I have a data frame called "finaldf"
>
>> names(finaldf)
>   [1] "especie" "estrato" "oc1"     "oc2"     "oc3"     "oc4"     "oc5"
> "oc6"
>   [9] "oc7"     "oc8"     "oc9"     "oc10"    "oc11"    "oc12"    "oc13"
>   "oc14"
> [17] "oc15"    "oc16"    "oc17"    "oc18"    "oc19"    "oc20"
>
> I tried (gave me  a data frame):
>
> DET <- cbind(finaldf[, 3:22])
>
>> head(DET)
>     oc1 oc2 oc3 oc4 oc5 oc6 oc7 oc8 oc9 oc10 oc11 oc12 oc13 oc14 oc15 oc16
> oc17 oc18
> 1    0   0   0   0   0   0   0   0   1    0    0    0    0    0    0    0
>   0    0
> 27   0   0   0   1   0   0   0   0   0    0    0    0    0    0    0    1
>   0    0
> 53   0   0   0   0   0   0   0   0   0    0    0    0    0    0    0    0
>   0    0
> 2    1   1   1   1   1   1   0   1   1    1    1    1    0    1    0    1
>   1    1
> 28   1   0   1   0   1   1   1   1   1    1    1    1    0    1    1    1
>   1    0
> 54   1   1   1   1   1   1   1   1   0    0    0    1    1    0    1    0
>   0    0
>     oc19 oc20
> 1     0    0
> 27    1    0
> 53    0    0
> 2     1    1
> 28    1    0
> 54    0    1
>
> and gave me a different results when I tried (gave me a matrix):
>
> DET <-  cbind(finaldf$oc1, finaldf$oc2, finaldf$oc3, finaldf$oc4,
> finaldf$oc5, finaldf$oc6, finaldf$oc7, finaldf$oc8, finaldf$oc9,
> finaldf$oc10, finaldf$oc11, finaldf$oc12, finaldf$oc13, finaldf$oc14,
> finaldf$oc15, finaldf$oc16, finaldf$oc17, finaldf$oc18, finaldf$oc19,
> finaldf$oc20)
>
>> head(DET)
>       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13]
> [,14]
> [1,]    0    0    0    0    0    0    0    0    1     0     0     0     0
>    0
> [2,]    0    0    0    1    0    0    0    0    0     0     0     0     0
>    0
> [3,]    0    0    0    0    0    0    0    0    0     0     0     0     0
>    0
> [4,]    1    1    1    1    1    1    0    1    1     1     1     1     0
>    1
> [5,]    1    0    1    0    1    1    1    1    1     1     1     1     0
>    1
> [6,]    1    1    1    1    1    1    1    1    0     0     0     1     1
>    0
>       [,15] [,16] [,17] [,18] [,19] [,20]
> [1,]     0     0     0     0     0     0
> [2,]     0     1     0     0     1     0
> [3,]     0     0     0     0     0     0
> [4,]     0     1     1     1     1     1
> [5,]     1     1     1     0     1     0
> [6,]     1     0     0     0     0     1
>
> Best,
>
> Manuel
>
>
>
>
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