Add margins to multi-way tables in R

Question

I have the following code in R to build a three-way contingency table:

txt="   death_p yes no
v_race  d_race      
white   white   53  414
black   11  37
black   white   0   16
black   4   139"

mytable = as.table(read.ftable(textConnection(txt)))
mytable = addmargins(mytable, margin=c(1))

It prints correctly

             death_p yes  no
v_race d_race                
white  white           53 414    
       black           11  37
black  white            0  16
       black            4 139
Sum    white           53 430
       black           15 176

I'd like to add a "percentage_yes" after the column "no" preserving the structure of the table.

                 death_p yes  no  %yes
v_race d_race                
white  white             53   414  0.11    
       black             11   37   0.00
black  white             0    16   0.11
       black             4    139  0.23
Sum    white             53   430  0.28
       black             15   176  0.79

I've tried with

subset(as.data.frame(prop.table(mytable, c(1,2))), death_p=="yes", select=c("Freq"))

but I don't know how to add this new column to the table using Abind (from DescTools). I don't know if there is possibly a better way to accomplish this. Thanks in advance for your help.

Hi, your shown output does not correspond to the actual output, could you edit that? And what should the final result look like? — jay.sf, May 28 '20 at 07:22
What kind of percentages are you exactly looking for? I doubt that it's a good idea to first calculate the marginal sums and then get some percentages... ;-) — Andri Signorell, May 29 '20 at 13:33
I need the percentage of people sentenced to death. I achieved this with p_yes = function(x) x[1]/sum(x); mytable = addmargins(mytable, margin=c(3), FUN = list(p_yes)) — Luigi Tiburzi, Jun 01 '20 at 09:46

score 2 · Accepted Answer · answered Jun 01 '20 at 09:49

For those who might be interested, I managed to do this by defining a function to calculate the percentage and then pass it to addmargins.

p_yes = function(x) x[1]/sum(x)
mytable = addmargins(mytable, margin=c(3), FUN = list(p_yes))

It gives

               death_p   yes     no     %yes
v_race d_race                
white  white             53.00   414.00  0.11    
       black             11.00   37.00   0.00
black  white             0.00    16.00   0.11
       black             4.00    139.00  0.23
Sum    white             53.00   430.00  0.28
       black             15.00   176.00  0.79

Add margins to multi-way tables in R

1 Answers1