Xline stata date format1/15/2024 But Stata internally stores dates and times as integers and reads them as numeric values. Usually we do not need to worry about the storage types, and Stata will take care of that and find the most efficient ways to store data.ĭates and times usually come in the human readable string forms, such as “Ma16:15 pm”, “2017.03.22 16:15” etc. Storage types affect mainly how much memory will be needed. Strings are stored as str#, where # indicates the maximum length of the string. Numeric values are stored as five types differing in range and accuracy: byte, int, long, float or double. This example applies to Stata editions 13 and 14.Dates and Times Data types and storage types Also remember to open the formatted date column as text to keep the formatted date in tact! If you wish to keep the dates with the (changed) formatting you need to export/save the file as a (delimited) text file using the command: export delimited filename.txt and then open the text file in Excel using the text wizard. Important: If you export a formatted file from Stata to an Excel file you will lose the formatting for the dates you just did. If you want to know all the options for formatting dates you can use the Help command: help datetime display formats. In this instance dates will be formatted with 4 digits for a year, for example: 19871022 Another example that may be useful for using with the Event Tool in the CRSP database is: There are a lot more options to change the dateformat. When you work with older dates it is wiser to use 4-digit year formats to avoid confusion. Negative integer numbers in Stata represent older dates. Where in Excel number 1 represents 1-1-1900 in Stata the number 1 represents 1-1-1960. Interesting sidenote: in Stata dates are actually integer numbers, just like in Excel. On the right side you also see that dates in Stata are actually variables of the type Integer = a number that can be written without a fractional component ( Wikipedia). If you look closely you see that “ under water” the variable still looks as it is originally presented: the first date 20-08-07 still looks like 20aug2007. Now I use the command to change the look of variable dateff: format dateff %tdDD-NN-YY. DD = day with two digits, NN = month with two digits and YY = Year with two digits. %tdDD-NN-YY = indicates that the timedate variable should look like 17-02-99. Variablename = indicates the date/variable item you wish to change Now if you are working with a dataset in Stata you can use a command to do a similar thing: format %tdDD-NN-YY The Dutch version looks similar: =TEKST(A1 ”dd-mm-jj”)Īfterwards you still have to copy and the paste as values to get workable dates for Datastream. In Excel you can use the command =TEXT(A1,”dd-mm-yy”). When you work with data and intend to do an event study using the Request Table option from Datastream you may have to change the date format for the event dates to something that Datastream understands (also depends on the date format used by the computer). There are many commands available and one command is very handy when it comes to changing date formats. This program can handle a lot of data and uses commands to edit data or analyse it. The past few weeks I have been learning about and working with Stata. Warning: WRDS and Two-Factor Authentication.
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