CODEWITHSUNDEEP
stata
user42459
user42459

Reputation: 915

Nonsense date coming from year and month function

I have a birthtime variable:

birthtime 
1976m2
1979m8

I ran the following:

gen birthyear=year(birthtime)
gen birthmonth=month(birthtime)

However, the result is nonsense.

Do the year and month functions not work for this format?

How can I retrieve year and month from the birthtime variable?

Upvotes: 1

Views: 79

Answers (2)

user42459
user42459

Reputation: 915

I found that the following does the job.

gen int temp = dofm(birthtime)
gen int birthyear = year(temp)
gen byte birthmonth = month(temp)

The result is

birthyear birthmonth
1976         2
1979         8

Upvotes: 1

user8682794
user8682794

Reputation:

You need to study Stata's SIF-to-SIF conversions:

clear

input birthtime
403
404
405
406
407
end

generate birthyear = year(dofm(birthtime))
generate birthmonth = month(dofm(birthtime))

list, abbreviate(10)

     +------------------------------------+
     | birthtime   birthyear   birthmonth |
     |------------------------------------|
  1. |       403        1993            8 |
  2. |       404        1993            9 |
  3. |       405        1993           10 |
  4. |       406        1993           11 |
  5. |       407        1993           12 |
     +------------------------------------+

Also:

format %tm birthtime

list, abbreviate(10)

     +------------------------------------+
     | birthtime   birthyear   birthmonth |
     |------------------------------------|
  1. |    1993m8        1993            8 |
  2. |    1993m9        1993            9 |
  3. |   1993m10        1993           10 |
  4. |   1993m11        1993           11 |
  5. |   1993m12        1993           12 |
     +------------------------------------+

Upvotes: 3

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