conformability error r(503) when looping matrix

[Kay Marcus]

Hello statalists,

I'm trying to loop some basic descriptive stats of age according to sex. Right now the matrix looks like this:

age[1,5]

	mu_men	sd_men	mu_women	sd_women	p
Age	48.584151	22.583488	51.528371	22.524248	.

with codes:

matrix age = J(1,5,.)
matrix rownames age = "age"
matrix colnames age = "mu_men" "sd_men" "mu_women" "sd_women" "p"

tab1 sex if index==1

local j=1
local s=1 // s is for values of sex (1 = Men, 0 = Women)

while (`s'>=0){

quietly sum age if sex==`s' & index==1, detail
local mu=r(mean)
local sd=r(sd)


matrix age[1,`j']=`mu'
matrix age[1,`j'+1]=`sd'

local s=`s'-1
local j=`j'+2
}

But I would like to have the matrix to look like this:

	mu	sd
men
women

So I wrote the following codes:

matrix age = J(2,3,.)
matrix rownames age= "men" "women"
matrix colnames age= "mu" "sd" "p"
local s=1

while (`s'>=0) {

sum age if sex==`s' & index==1, detail
local mu=r(mean)
local sd=r(sd)

matrix age[`s',1]=`mu'
matrix age[`s',2]=`sd'

local s=`s'-1
}

I end up getting this error message: conformability error
r(503);

When I list the matrix, this is what I get:

	mu	sd	p
men	48.584151	22.583488	.
women	.	.	.

Why am I getting this error? It seems to happen as soon as Stata is trying to run the second row. How do I fix it? I am using Stata 15.1 on a PC, thanks!

[William Lisowski]

Welcome to Statalist.

You have accidentally posted your topic in Statalist's Mata Forum, which is used for discussions of Stata's Mata language, which is different than Stata's command language, and different than Stata's matrix commands. Your question would have seen a more appropriate, and much larger audience if you had posted it in Statalist's General Forum.

Also, if you have not already done so, take a look at the Statalist FAQ linked to at the top of this page for posting guidelines and suggestions.

With all that said, your problem is that your code attempts to store the results for women (s=0) into row 0 of your matrix. That can't be right and may be what is causing the error. Perhaps the following untested changes will start you in a useful direction.

local s=1
local j=1

while (`s'>=0) {

sum age if sex==`s' & index==1, detail
local mu=r(mean)
local sd=r(sd)

matrix age[`j',1]=`mu'
matrix age[`j',2]=`sd'

local s=`s'-1
local j=`j'+1
}

[Kay Marcus]

I see, sorry for the mispost. Thanks a lot for the response!