On May 7, 2014, at 5:15 AM, Abhinaba Roy <abhinabaro...@gmail.com> wrote:
> Hi R-helpers,
>
> sumx <- summary(mtcars[,c("mpg","disp")])
>> sumx
> mpg disp
> Min. :10.40 Min. : 71.1
> 1st Qu.:15.43 1st Qu.:120.8
> Median :19.20 Median :196.3
> Mean :20.09 Mean :230.7
> 3rd Qu.:22.80 3rd Qu.:326.0
> Max. :33.90 Max. :472.0
>
> I want a dataframe as
>
> mpg disp
> Min. 10.40 71.1
> 1st Qu. 15.43 120.8
> Median 19.20 196.3
> Mean 20.09 230.7
> 3rd Qu. 22.80 326.0
> Max. 33.90 472.0
>
> How can it be done in R?
> --
> Regards
> Abhinaba Roy
summary(), when applied to multiple columns, as you are doing, returns a
character table object:
> str(sumx)
'table' chr [1:6, 1:2] "Min. :10.40 " "1st Qu.:15.43 " ...
- attr(*, "dimnames")=List of 2
..$ : chr [1:6] "" "" "" "" ...
..$ : chr [1:2] " mpg" " disp"
Note that the actual table elements contain both character and numeric values
that have been formatted.
If you use:
> sapply(mtcars[, c("mpg", "disp")], summary)
mpg disp
Min. 10.40 71.1
1st Qu. 15.42 120.8
Median 19.20 196.3
Mean 20.09 230.7
3rd Qu. 22.80 326.0
Max. 33.90 472.0
this applies the summary() function to each column separately, returning a
numeric matrix:
> str(sapply(mtcars[, c("mpg", "disp")], summary))
num [1:6, 1:2] 10.4 15.4 19.2 20.1 22.8 ...
- attr(*, "dimnames")=List of 2
..$ : chr [1:6] "Min." "1st Qu." "Median" "Mean" ...
..$ : chr [1:2] "mpg" "disp"
If you actually want a data frame, you can coerce the result:
> as.data.frame(sapply(mtcars[, c("mpg", "disp")], summary))
mpg disp
Min. 10.40 71.1
1st Qu. 15.42 120.8
Median 19.20 196.3
Mean 20.09 230.7
3rd Qu. 22.80 326.0
Max. 33.90 472.0
> str(as.data.frame(sapply(mtcars[, c("mpg", "disp")], summary)))
'data.frame': 6 obs. of 2 variables:
$ mpg : num 10.4 15.4 19.2 20.1 22.8 ...
$ disp: num 71.1 120.8 196.3 230.7 326 ...
Regards,
Marc Schwartz
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