The Iteration Station » SAS

Creating a Cartesian Product in SAS

bkloss — Fri, 13 Feb 2009 06:49:48 +0000

Here’s the first of several question/answer posts.

Feel free to write me with your SAS question and I’ll provide the answer in a post.

Question

Suppose I have two SAS datasets, set A contains 5 variables having 3000 unique records and set B contains just 1 variable having 500 unique records (just a bunch of ID numbers). Suppose I would like to create a new dataset where each of the records from set A would be duplicated so that the first record would be repeated 500 times where each of those would be paired with a unique ID from set B. The goal is to have the new dataset with 6 variables (the five from A and the one from B) containing a total of 1,500,000 records produced in this way.

Any help or suggestions you can provide is greatly appreciated.

Answer

What you are asking for is called a Cartesian Product. All possible combination of rows in all tables.

This can be accomplished with the following SAS code

PROC SQL noprint;

Create Table as

select *
from , ;
quit ;

SAS Resume Tools

bkloss — Wed, 04 Feb 2009 22:00:37 +0000

Although you may consider yourself an Analyst, during your job search you need to think like a salesman . Every interaction with a prospective employer is a golden opportunity to sell yourself. Submitting a resume is equivalent to cold calling a client so stick your foot in the door by connecting quickly with the hiring manager. At a glance, this person needs to see what they’re looking for or else your resume will hit the bottom of the pile, or worse, the paper shredder.

The simple tools provided below turn any SAS Job resume into a targeted sales weapon. The first visualization displays the words that occur most commonly among 450 SAS job postings from SASJobs.BlogSpot.com and SASJobs.com . Make sure you address each of these terms appropriately in your resume and personal statement. The bigger the word, the more commonly it was used- act accordingly. If you want to drill down even further, click on the layout drop down to increase the maximum number of terms shown.

These Visualizations work best in Fire Fox ————- Make sure to have Java enabled

So, you know what terms to target, now the question becomes, what do I say about them? Well, have no fear. The next tool displays exactly how keywords were used in our set of job descriptions. Take an important term and type it into the search bar. Hit enter and a tree will appear that shows you how the phrase was used in the job postings. As an example, a search for ‘SQL’ yields a tree that indicates companies are looking for people with knowledge of proc SQL, SQL programming and sql server. If I click on the next term in a brach the tree will again expand and I can see that job posts also reference oracle databases in the same sentence. This tool provides many examples of many related skills that company are looking for and can help the job searcher represent thier experience in a way that will have HR salivating.

Sorting Data in SAS with Proc Sort

bkloss — Sun, 18 Jan 2009 19:54:52 +0000

The SAS Sort Procedure

Sorting data in SAS is an everyday task accomplished for a variety of reasons.

Certain types of reports require that data be presorted to present results accurately.
Programs that include a where statement can execute more quickly on a sorted data set.
Unlike SQL, SAS requires data sets to be sorted by a common variable before a join operation can occur.

These examples are just a few situations where a presorted data set is necessary or essential. Luckily, PROC SORT is a relatively simple procedure. The Basic Syntax is below:

Proc Sort data =;

By ;

Run ;

In the code above, is both the input and output data set of the procedure. Essentially, SAS replaces your old data set with the new sorted version. If data= is not specified, SAS will sort the last data set in use.

By Statement

The By statement specifies the variables to use as sort keys. You may include as many by variables as are contained in the data set. If you include more than one by variable, SAS will sort the data by the first by variable, then sort the groups of observations produced from the previous sort by the second variable. SAS automatically sorts data in ascending order, meaning it stores values from A to Z or in the case of numbers, from lowest to highest. To sort in descending order (from Z to A), specify the keyword Descending before the variable that you would like to sort by.

This sample code produces the example below:

Proc Sort data =example;

By Cost Descending Class;

Run ;

Notice how within each group of ascending cost values, the class values are listed in descending order. Also note that the missing value for the last row is considered a low value and is placed after C. SAS treats missing values for character and numeric data as very small values.

OUT=

you wanted to retain the original unsorted data while creating a new sorted data set, you can include the out = as shown below:

Proc Sort data = out = ;

By Cost Descending Class;

Run ;

This option saves the sorted output data set in a new location and retain the original unsorted data set.

NODUPKEY

If you wanted to include only unique values in your output data set. The NODUPKEY option will eliminate all duplicate values during the sort. Let us return to our example, this time incorporating all that we have learned. We will sort the data set ‘Old’ by the variables cost and descending class to produce an output data set ‘New’. The code below produces the example picture:

Proc Sort data = out = NODUPKEY ;

By Cost Descending Class;

Run ;

Notice how the duplicate observation (43, D) from the previous picture has been removed. A message was printed to the SAS log indicating that the duplicate record was removed:

That wrap things up for the first entry of the SAS tip series. Please feel free to leave comments if you have anything to add about the Proc Sort procedure.

Base SAS Certification after two months?

bkloss — Fri, 05 Sep 2008 05:04:53 +0000

Yes, it can be done.

I passed the Base SAS Certification after only 2 months working with the tool.

That being said, I truly crammed my bum off to make the grade.

I can’t blame SAS for creating a tough exam because the benefits of certification are clear. This is what SAS has to say about obtaining certification…

With a professional certification from SAS you will set yourself apart from the competition by earning the only globally-recognized credential endorsed by SAS. Put your SAS skills to the test today and reap the benefits tomorrow.

Increases your career opportunities and marketability

Enhances your credibility as a technical professional

Assesses your knowledge of SAS software

Allows you to earn industry validation for your knowledge

Durn Right!

So, here’s how a green thumb went about preparing for the big day…

Prerequisites:

Set aside at least 80 hours for study if you are totally new to SAS
Save your pennies because the best materials don’t come cheap

Resources:

SAS Self-Paced E learning. This one is expensive but it provides an interactive way to step through all the material covered on the exam. It also includes a practice test that is similar in format and content to the real exam.
SAS Notes and Samples. Here’s a set of free resources that can get you acquainted with many of the topics found in the exam.
Unofficial SAS cert Blog. Here’s a collection of difficult questions that will explain some of the in depth complexity of SAS coding.

So, check out the resources and you too can reap the benefits of SAS certification.