Quick Table for Converting Different Dates to Stata Format

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Quick Table for Converting Different Dates to Stata Format

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Daily Dates

Copying data from the internet, CSV files, or other sources into Stata will record the date as a string variable, shown with red color. Before we can use the Stata time-series or panel-data capabilities, we need to convert the string date to a Stata date. In the following table, the first column shows different date formats in which the date is already recorded and brought into Stata. To convert them into a Stata date, an example code is shown in the second column. Once the date is converted into a Stata readable format, we need to format the date so that the visual display of the date is human-readable. We can do that by using the %td format, for example, we can use the code format mydate %td

text Code Output
15/1/2015
gen mydate=date(text, "MDY")
15feb2015
15/1/2015
gen mydate=date(text, "MDY")
15feb2015
2015/1/15
gen mydate=date(text, "YMD")
15feb2015
201502
gen mydate=date(text, "MY")
1feb2015
1/15/08
gen mydate=date(text,"MDY",1999)
15jan1908
1/15/08
gen mydate=date(text,"MDY",2019)
15jan2008
1/15/51
gen mydate=date(text,"MDY",2000)
15jan1951
1/15/01
gen mydate=date(text,"MDY",2050)
15jan2001
1/15/00
gen mydate=date(text,"MDY",2050)
15jan2000
20060125
gen mydate=date(text, "YMD")
25jan2006
060125
gen mydate=date(text, "20YMD")
25jan2006


Example using some data

* Enter example data
clear
input str9 text
"15/1/2015"
end

* Now convert the variable text to Stata date
gen mydate=date(text, "DMY")

* Change the display format
format mydate %td

 

From daily to other frequencies

From daily to Code
weekly
gen weekly_date = wofd(daily_date)
Monthly
gen monthly_date = mofd(daily_date)
Quarterly
gen qyarterly_date = qofd(daily_date)
Yearly
gen year = year(daily_date)

 

 

Example using some data

* Enter example data
clear
input str9 text
"15/1/2015"
end

* Now convert the variable text to Stata date
gen daily_date=date(text, "DMY")
format daily_date %td


* Create a weekly date
gen weekly_date = wofd(daily_date)
format weekly_date %tw

* Create a monthly date
gen monthly_date = mofd(daily_date)
format monthly_date %tm

* Create a quarterly date
gen quarterly_date = qofd(daily_date)
format quarterly_date %tq

* Create a yearly date
gen year = year(daily_date)

 

 

From other frequencies to daily

If we already have dates in weekly, monthly, or quarterly frequencies, we can convert them back to daily dates. The second column in the following table provides an example of a given format in which the date is already recorded, and the third column presents the code which shall create a daily date. To see the codes in action, download this do file and execute. The file extension should be changed from doc to do after download. 

From  given_date Code
weekly
2018w46
gen daily_date = dofw(given_date)
Monthly
2018m11
gen daily_date = dofm(given_date)
Quarterly
2018q4
gen daily_date = dofq(given_date)
Yearly
2018
gen daily_date = dofy(given_date)

 

Complex Conversions

If we already have dates in weekly, monthly, or quarterly frequencies, we can convert them back to daily dates and then to other frequencies. The second column in the following table provides an example of a given format in which the date is already recorded, and the third column presents the code which shall convert the date to the desired frequency.  

From  given_date Code
Weekly to monthly
2018w46
gen monthly_date = dofm(dofw(given_date))
Monthly to weekly
2018m11
gen weekly_date = dofw(dofm(given_date))
Quarterly to monthly
2018q4
gen monthly_date = dofm(dofq(given_date))
Monthly to quarterly
2018m11
gen quarterly_date = qofd(dofm(given_date))
Weekly to quarterly
2018w46
gen quarterly_date = qofd(dofw(given_date))
Quarterly to Weekly
2018q4
gen weekly_date = dofw(dofq(given_date))

 

 

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4 Comments

Testobe Agar

October 25, 2018at 4:06 pm

A very useful and concise post on Stata dates. I shall add it to my favorites and come back for quick reference when need to convert dates in Stata.

Shahzad Hussain

October 25, 2018at 11:29 pm

Great Sir

Hamid Shah

October 25, 2018at 11:30 pm

Sir aoa how can v get t values in outreg2 command?

    Attaullah Shah

    October 25, 2018at 11:33 pm

    You can use asdoc for regression output. asdoc provides three different regression outputs. The standard outreg2 regression output can be generated by asdoc as shown in this post For t-statistics, use the option rep(t)

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