Mastering the Art of Formatting Dates as SAS Dates: A Step-by-Step Guide

SAS dates can be a puzzle, especially for those new to the world of data analysis. But fear not, dear reader, for this article will unlock the secrets of formatting dates as SAS dates. By the end of this comprehensive guide, you’ll be a pro at working with dates in SAS, and your datasets will be singing in harmony.

What are SAS Dates, Anyway?

In SAS, dates are stored as numeric values, representing the number of days since January 1, 1960. This might seem strange at first, but it’s a clever system that allows for efficient date calculations and comparisons. To work effectively with dates in SAS, you need to understand how to format them correctly.

The Importance of Correct Date Formatting

Imagine you’re working on a project that involves analyzing sales data over the past year. You have a column containing dates in the format ‘dd/mm/yyyy’, but SAS is throwing errors because it can’t recognize them as dates. Frustrating, right? By formatting your dates correctly, you can avoid such headaches and focus on extracting valuable insights from your data.

Common Date Formats and Their SAS Equivalents

Before we dive into the nitty-gritty of formatting dates, let’s take a look at some common date formats and their SAS equivalents:

Date Format	SAS Equivalent
dd/mm/yyyy	DDMMYY10.
mm/dd/yyyy	MMDDYY10.
yyyy-mm-dd	YYMMDD10.
dd-mon-yyyy	DDMONYY8.

Converting Dates to SAS Format using the INPUT Function

One way to convert dates to SAS format is by using the INPUT function. This function takes two arguments: the value to be converted and the informat (the format of the value). Here’s an example:

data dates;
  input date_str $10.;
  date_sas = input(date_str, DDMMYY10.);
  format date_sas date9.;
cards;
01/01/2022
02/15/2021
03/20/2020
;
run;

In this example, we’re using the DDMMYY10. informat to convert the date string ’01/01/2022′ to a SAS date. The resulting date_sas variable will be stored as a numeric value, representing the number of days since January 1, 1960.

Converting SAS Dates to Human-Readable Format using the PUT Function

Now that we’ve converted our dates to SAS format, let’s explore how to convert them back to a human-readable format using the PUT function.

data dates;
  date_sas = '01jan2022'd;
  date_str = put(date_sas, DDMMYY10.);
  put date_str;
run;

In this example, we’re using the PUT function to convert the SAS date ’01jan2022’d to a date string in the format ‘dd/mm/yyyy’. The resulting date_str variable will contain the string ’01/01/2022′.

Using the FORMAT Statement to Specify Date Format

Another way to control the format of your dates is by using the FORMAT statement. This statement allows you to specify the format of a variable when it’s displayed or printed.

data dates;
  date_sas = '01jan2022'd;
  format date_sas date9.;
  put date_sas;
run;

In this example, we’re using the FORMAT statement to specify that the date_sas variable should be displayed in the format ‘dd/mm/yyyy’. The resulting output will be ’01/JAN/2022′.

Tips and Tricks for Working with Dates in SAS

Here are some additional tips and tricks to keep in mind when working with dates in SAS:

• Use the TODAY() function to get the current date.
• Use the MDY() function to convert month, day, and year values to a SAS date.
• Use the INTNX() function to perform date calculations, such as adding or subtracting days, months, or years.
• Use the YEAR() function to extract the year from a SAS date.
• Use the MONTH() function to extract the month from a SAS date.
• Use the DAY() function to extract the day from a SAS date.

Common Date-Related Errors and How to Avoid Them

We’ve all been there – staring at a SAS log filled with errors, wondering what went wrong. Here are some common date-related errors and how to avoid them:

1. Error: “Invalid date value”

   Solution: Check your date format and make sure it matches the informat used in the INPUT function.

2. Error: “Date value out of range”

   Solution: Check your date value and make sure it’s within the range of valid dates (January 1, 1582, to December 31, 19,938).

3. Error: “Informat not recognized”

   Solution: Check your informat and make sure it’s correctly specified. Refer to the SAS documentation for a list of valid informats.

Conclusion

Formatting dates as SAS dates might seem like a daunting task, but with practice and patience, you’ll become a master of date manipulation. Remember to use the INPUT function to convert dates to SAS format, the PUT function to convert SAS dates to human-readable format, and the FORMAT statement to specify date format. And, of course, don’t forget to keep an eye out for those pesky date-related errors!

With this comprehensive guide, you’re well on your way to becoming a SAS date expert. Go forth, format those dates, and uncover the insights hidden within your data!

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