number of columns (variables)?

[River Huang]

Dear All, I found this question here. The question is that how we count the number of columns in the data set. For example,

* Example generated by -dataex-. To install: ssc install dataex
clear
input str3 X float Y str5 Z str3(P Q)
"一" 1 "one"   "Ⅰ" "①"
"二" 2 "two"   "Ⅱ" "②"
"三" 3 "three" "Ⅲ" "③"
"四" 4 "four"  "Ⅳ" "④"
"五" 5 "five"  "Ⅴ" "⑤"
"六" 6 "six"   "Ⅵ" "⑥"
end

there are 5 columns. Any suggestions are appreciated.

[Rich Goldstein]

I may well be missing something in your question, but if you use -describe-, possibly with options to reduce the output or even -quietly-, the number of variables is returned in "r(k)" - there are other commands that also return this information

[Nick Cox]

Rich Goldstein is right; and let's add that creturn list hints that

di c(k)

returns the number of variables too.

[William Lisowski]

The number of variables in the dataset currently active is stored in Stata's c-class value returned by c(k).

. clear all

. display c(k)
0

. sysuse auto
(1978 Automobile Data)

. display c(k)
12

. frame put make price, into(cars)

. display c(k)
12

. frame cars: display c(k)
2

[River Huang]

Dear @Rich Goldstein, @Nick Cox, and @William Lisowski, Thank you all for these helpful suggestions.