Dates and Times

1
Dates and Times

• SAS Date, Time and Date-Time Formats

2
Date Storage

• SAS stores Dates, Times and Date-Time values
  differently.
• Datetime seconds between January 1, 1960 and
  an hour/minute/second within a specified date
• Time seconds since midnight of the current day
• Date days between January 1, 1960, and a
  specified date

3
Functions

• Functions that extract dates and times from
  datetime variables
• DATEPART(variable) extracts the date from a SAS
  datetime value
• TIMEPART(variable) extracts the time from a SAS
  datetime value

4
Creating datetime variables

• Functions can convert numeric values to datetime
  values
• MDY(month,day,year) gives a date value
• birthdaymdy(8,27,90)
• HMS(hour,minute,second)
• hridhms(12,45,10)

5
Current Dates and Times

• The following functions extract current values
• DATETIME()
• DATE()
• TIME()
• These functions have no arguments

6
Parts of date Values

• Return numeric values from date values
• DAY(date)
• MONTH(date)
• YEAR(date)
• WEEKDAY(date)
• QTR(date)

7
Parts of time or datetime values

• HOUR(lttime datetimegt)
• MINUTE(lttime datetimegt)
• SECOND(lttime datetimegt)

8
PUT and INPUT functions

• PUT(source, format.) creates a character value
• Source can be any format
• Format must be the same type as the source
• INPUT(source, lt? ??gtinformat.) creates a value
  based on the informat
• Source is a character expression
• ? or ?? suppress error messages in the log
• Informat you want to apply

9
Examples

• Character to numeric
• Sale INPUT(2,115,353,comma9.)
• Converting to character
• Data Test
• dateval put(123456,mmddyy8.)
• put dateval
• run
• Produces 01/04/98 in the SAS log

10
Formats and Informats

• Formats describe the way variables are written
• Always contain a period
• Start with a if the variable being modified is
  character, not otherwise
• Informats describe the way variables are read
• Always contain a period
• Start with a if the variable is to be stored as
  character
• Formats and informats generally have the same
  syntax
• most formats are also informats and vice-versa

11
Useful datetime formats

• DATEw. writes date values in the form ddmmmyy or
  ddmmmyyyy
• DATETIMEw.d writes datetime values in the form
  ddmmmyyhhmmss.ss
• Note what is printed depends on the w value
• DOWNAMEw. writes date values as the name of the
  day of the week
• WORDDATEw. writes date values in words
• Etc. There are many more useful formats.