How to check if number of distinct observations is same for two variables?

[Titir Bhattacharya]

Hi,

I have generated new ID variable and want to check if the number of distinct observations indicated by new ID is the same as indicated by the original ID.

Here is the sample data:

* Example generated by -dataex-. To install: ssc install dataex
clear
input str13(new_hhid temp_hhid)
"10020040009" "1    2  1   9"
"10020040009" "1    2  1   9"
"10020040017" "1    2  1  17"
"10020040017" "1    2  1  17"
"10020040017" "1    2  1  17"
"10020040017" "1    2  1  17"
"10020040033" "1    2  1  33"
"10020040033" "1    2  1  33"
"10020040033" "1    2  1  33"
"10020040033" "1    2  1  33"
"10020040041" "1    2  1  41"
"10020040041" "1    2  1  41"
"10020040041" "1    2  1  41"
"10020040049" "1    2  1  49"
"10020040049" "1    2  1  49"
"10020040049" "1    2  1  49"
"10020040057" "1    2  1  57"
"10020040057" "1    2  1  57"
"10020040057" "1    2  1  57"
"10020040057" "1    2  1  57"
"10020040057" "1    2  1  57"
"10020040065" "1    2  1  65"
"10020040065" "1    2  1  65"
"10020040065" "1    2  1  65"
"10020040073" "1    2  1  73"
"10020040073" "1    2  1  73"
"10020040073" "1    2  1  73"
"10020040073" "1    2  1  73"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040089" "1    2  1  89"
"10020040113" "1    2  1 113"
"10020040113" "1    2  1 113"
"10020040113" "1    2  1 113"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040121" "1    2  1 121"
"10020040129" "1    2  1 129"
"10020040137" "1    2  1 137"
"10020040145" "1    2  1 145"
"10020040145" "1    2  1 145"
"10020040145" "1    2  1 145"
"10020040153" "1    2  1 153"
"10020040153" "1    2  1 153"
"10020040153" "1    2  1 153"
"10020040177" "1    2  1 177"
"10020040201" "1    2  1 201"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040209" "1    2  1 209"
"10020040217" "1    2  1 217"
"10020040217" "1    2  1 217"
"10020040233" "1    2  1 233"
"10020040233" "1    2  1 233"
"10020040233" "1    2  1 233"
"10020040241" "1    2  1 241"
"10020040249" "1    2  1 249"
"10020040249" "1    2  1 249"
"10020040249" "1    2  1 249"
"10020040257" "1    2  1 257"
"10020040257" "1    2  1 257"
"10020040257" "1    2  1 257"
"10020040257" "1    2  1 257"
"10020040257" "1    2  1 257"
"10020040257" "1    2  1 257"
"10020040273" "1    2  1 273"
"10020040273" "1    2  1 273"
"10020040273" "1    2  1 273"
"10020040273" "1    2  1 273"
"10020040273" "1    2  1 273"
"10020040273" "1    2  1 273"
"10020040281" "1    2  1 281"
"10020040281" "1    2  1 281"
"10020040281" "1    2  1 281"
"10020040289" "1    2  1 289"
"10020040289" "1    2  1 289"
"10020040289" "1    2  1 289"
"10020040289" "1    2  1 289"
"10020050054" "1    2  2  54"
"10020050054" "1    2  2  54"
"10020050054" "1    2  2  54"
"10020050054" "1    2  2  54"
"10020050054" "1    2  2  54"
"10020050054" "1    2  2  54"
end

new_hhid is the id I have generated. temp_hhid is that available in the original data. I need to check if I have generated the id properly and would like to check whether number of distinct observations in new_hhid is the same as in temp_hhid.

Would appreciate any help

Thanks

[Øyvind Snilsberg]

distinct (SSC),

. distinct new_hhid temp_hhid

           |        Observations
           |      total   distinct
-----------+----------------------
  new_hhid |        100         27
 temp_hhid |        100         27

[Titir Bhattacharya]

distinct (SSC),

. distinct new_hhid temp_hhid

| Observations
| total distinct
-----------+----------------------
new_hhid | 100 27
temp_hhid | 100 27

Thanks. This worked perfectly

[Nick Cox]

distinct is more up-to-date at the Stata Journal site.

.  search distinct, sj

Search of official help files, FAQs, Examples, and Stata Journals

SJ-20-4 dm0042_3  . . . . . . . . . . . . . . . . Software update for distinct
        (help distinct if installed)  . . . . . .  N. J. Cox and G. M. Longton
        Q4/20   SJ 20(4):1028--1030
        sort() option has been added

A bigger deal for the likely underlying question here is that having the same number of distinct values doesn't guarantee that two variables line up one to one, a question addressed at https://www.stata.com/support/faqs/d...ions-in-group/