[R] Aggregate individual level data to age categories

[stei@@@duke m@iii@g oii gm@ii@com]

Thank you, this is already very helpful.

But how do I get it in the form
age  var_x=1  var_x=2  var_x=3
45     1              1             0
46      1              0            0

So it would be a data frame with 4 variables.

Cheers!

On Wed, Feb 12, 2020 at 10:25 PM William Dunlap <wdunlap using tibco.com> wrote:
>
> You didn't say how you wanted to use it as a data.frame, but here is one way
>
> d <- data.frame(
>     check.names = FALSE,
>     age = c(45L, 45L, 46L, 47L, 47L),
>     x = c(1L, 2L, 1L, 3L, 3L))
> with(d, as.data.frame(table(age,x)))
>
> which gives:
>   age x Freq
> 1  45 1    1
> 2  46 1    1
> 3  47 1    0
> 4  45 2    1
> 5  46 2    0
> 6  47 2    0
> 7  45 3    0
> 8  46 3    0
> 9  47 3    2
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
>
> On Wed, Feb 12, 2020 at 1:12 PM stefan.duke using gmail.com <stefan.duke using gmail.com> wrote:
>>
>> well, if I think about, its actually a simple frequency table grouped
>> by age. but it should be usable a matrix or data frame.
>>
>> On Wed, Feb 12, 2020 at 9:48 PM <cpolwart using chemo.org.uk> wrote:
>> >
>> > So a pivot table?
>> >
>> > On 12 Feb 2020 20:39, stefan.duke using gmail.com wrote:
>> >
>> > Dear All,
>> >
>> > I have a seemingly standard problem to which I somehow I do  not find
>> > a simple solution. I have individual level data where x is a
>> > categorical variable with 3 categories which I would like to aggregate
>> > by age.
>> >
>> > age x
>> > 45   1
>> > 45   2
>> > 46   1
>> > 47   3
>> > 47   3
>> > and so on.
>> >
>> > It should after transformation look like that
>> >
>> > age x_1 x_2 x_3
>> > 45    1     0   1
>> > 46    1     0   0
>> > 47     0    0   2
>> >
>> > Basically to calculate prevalences by age categories.
>> >
>> > Thanks for any pointers!
>> >
>> > Cheers!
>> >
>> > ______________________________________________
>> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>> >
>> >
>>
>> ______________________________________________
>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.