loop for cross tab

[Mukesh Punia]

Dear members,

Is there a way to use the loop for cross-tabulation?

X and y are categorical

What I am doing is-

tab y x1
tab y x2
.     .   .
.     .   .
.     .  .
tab y  xk

How to write a loop for keeping 'y' fixed and using 'x' for each next table?

Thank you!

[Clyde Schechter]

foreach v of varlist x1 x2 x3 ... xk {  // DON'T USE ... IN REAL CODE; LIST THE VARIABLES
    tab y `v'

will do that. But you really don't need a loop. You can just do:

tab2 y x1 x2 x3 ... xk, firstonly // AGAIN, DON'T USE ...; LIST THE VARIABLES

[Mukesh Punia]

Thank you, Schechter

foreach v of varlist x1 x2 x3 ... xk { // DON'T USE ... IN REAL CODE; LIST THE VARIABLES
tab y `v'

will do that. But you really don't need a loop. You can just do:

tab2 y x1 x2 x3 ... xk, firstonly // AGAIN, DON'T USE ...; LIST THE VARIABLES

Is it possible to write a loop including y1, y2, and y3 - which are also in dummy form?

[Clyde Schechter]

Yes

foreach v of varlist y1 y2 y3 {
    tab2 `v' x1 x2 x3 ... xk
}

[Bruce Weaver]

I'm sure Clyde meant to include the firstonly option in #4, as he did in #2.

foreach v of varlist y1 y2 y3 {
    tab2 `v' x1 x2 x3 ... xk, firstonly
}

[Clyde Schechter]

Indeed, I did. Thank you Bruce.

[Mukesh Punia]

Thank you!

One more clarification-

Only fweight is allowed with tab2

I'm sure Clyde meant to include the firstonly option in #4, as he did in #2.

foreach v of varlist y1 y2 y3 {
tab2 `v' x1 x2 x3 ... xk, firstonly
}

[Nick Cox]

Sometimes when a thread makes a turn -- in fact, my real problem is more complicated than I told you -- then the answer just is more complicated too.

If you want different weights, then the solution could be

1. Cloning tab2.ado and generalizing it to support different weights. Save your own command under a different name in your own filespace.

2. A double loop:

foreach y in y1 y2 y3 { 
     foreach x in x1 x2 x3 { 
           tab `y' `x' [aw=whatever] 
     }
}

Here solution #2 is what I recommend unless and until you use it so often that #1 looks attractive.

[Mukesh Punia]

Thank you, Dr. Cox

This is what I wanted!