[R] frequency table across multiple variables

Ivar Herfindal ivar.herfindal at bio.ntnu.no
Fri Sep 19 10:30:12 CEST 2008

```Hi

Here is an alternative solution which will include count of the NA. It
may not be "formally" correct, but it seems to work:

> mapply(function(x) table(factor(ifelse(is.na(x), "NA", x),
levels=c("NA",1,2,3,4))), m)
x1 x2 x3
NA  3  4  0
1   5  0  5
2   3  3  5
3   3  5  4
4   3  5  3
>

Hope this helps

Ivar Herfindal

Philipp Pagel skrev:
>> I have a dataframe like this:
>>
>> x1<-c(1,2,3,4,NA ,NA ,NA, 3, 1, 1, 1, 1, 2, 2, 3, 4, 4)
>> x2<-c(2,3,4,3,4,3,4,2,2,3,4,NA,NA,NA,NA,4,3)
>> x3<-c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,1,2)
>> m<-data.frame(x1,x2,x3)
>>
>> I would like to create a frequency table like this:
>>
>>       x1  x2  x3
>> NA
>> 1
>> 2
>> 3
>> 4
>>
>> where the values in each cell would be the count of the value for that
>> variable.
>> How can I do this?
>>
>
> The following will work IF all columns are integer:
>
>
>
>> apply(m, 2, function(x){tabulate(na.omit(x))})
>>
>      x1 x2 x3
> [1,]  5  0  5
> [2,]  3  3  5
> [3,]  3  5  4
> [4,]  3  5  3
>
> Please note that the result will look slightly different, if some columns contain
> the largest value and others don't:
>
>
>> x1<-as.integer(c(1,2,3,4,NA ,NA ,NA, 3, 1, 1, 1, 1, 2, 2, 3, 4, 5))
>> m<-data.frame(x1,x2,x3)
>> apply(m, 2, function(x){tabulate(na.omit(x))})
>>
> \$x1
> [1] 5 3 3 2 1
>
> \$x2
> [1] 0 3 5 5
>
> \$x3
> [1] 5 5 4 3
>
>
> cu
> 	Philipp
>
>
>

```