Sas hash object programming made easy pdf


 

This books (SAS Hash Object Programming Made Easy [FREE]) Made by Michele M. Burlew About Books Hash objects, an efficient look-up. Hash objects, an efficient look-up tool in the SAS DATA step, are object-oriented programming structures that function differently from traditional SAS language. 2 SAS Hash Object Programming Made Easy in your SAS programming toolkit. If you've already used hash objects some, then this book offers you some.

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Sas Hash Object Programming Made Easy Pdf

Multi-variable hash object Complex hash object. • Hash object structure is data key. Hash Object h. Program Data Vector .. Object Programming. Made Easy. The hash table is a widely used data structure in object oriented programming languages. SAS hash object to merge together subject level data without using sort/merge steps or sql joins. .. SAS Hash Object Programming Made Easy. Cary. HASH programming is a hot topic in the industry that started with SAS 9. This paper is intended data – it can be done via characters or numbers. Also, the data SAS. Syntax. To declare a hash object, you use the DECLARE statement. . terney.info pdf.

Completely updated for SAS 9. Expanded examples demonstrate how to combine data sets vertically and horizontally; retrieve data from lookup tables; modify and update data sets; combine summary and detail data sets; reshape and transpose observations in a data set; and manipulate data in a data set with utilities and functions. Unique features of this book include the following: Examples are grouped by task, not by code, so you can easily find a solution to a particular task; alternative solutions are presented in addition to the main examples; most examples that combine and modify data sets include both a DATA step and a PROC SQL solution; many examples include a "Closer Look" section that describes in-depth how the example helps you complete the task; and each example stands on its own so you do not need to read the book from beginning to end. Designed for SAS programmers at all levels, this examples book will help simplify the challenging task of combining and modifying data sets. Read more Collapse About the author Michele M. Burlew, president of Episystems, Inc. Her work involves writing programs to complete data cleaning, data analysis, and report-writing tasks. Read more.

The best introduction to the Hash Object that I know of. Plenty of great examples and written in an easily understandable language.

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If you are already familiar with merges and joins, you will have no problem learning about Hash Object reading this book. A hands on, non-theoretical approach to time series analysis and the many great procedure in ETS Econometrics and Time Series.

A must have for the beginner in the Output Delivery System. This book contains dozens of great tips to how to control how, what and where your results are outputted. If you are interested in even more control over your graph procedures and options, this is a great place to start. A short and precise book covering the basic statistical concepts you will usually face in an introductory statistics course.

This book has a way of explaining statistical concepts in a way that even non-statisticians may understand. I use this book as a reference work when I have to refresh the intuitive side of some field in statistics. Littell, Walter W.

Stroup and Rudolf J. If you want to learn about linear modelling in general using SAS programming, this is a good place to start. We will see t hat t he hash obj ect t able sat isfies it in t he pract ical sense. The at t ribut es of t he hash t able obj ect are keyed ent ries com prising it s key s and m aybe also sat ellit es. Before any hash t able obj ect m et hods can be called operat ions on t he hash ent ries perform ed , t he ob j ect m ust be d eclared.

Define a set of hash keys. DefineDat a. Define a set of hash t able sat ellit es. Alt hough a dum m y call can st ill be issued, it is not required.

Tell SAS t he definit ions are done. I nsert t he key and sat ellit es if t he key is not yet in t he t able ignore duplicat e keys. Delet e t he ent ire ent ry from t he t able, including t he key and t he dat a. Search for t he key. I f it is found, ext ract t he sat ellit e s from t he t able and updat e t he host Dat a st ep variables.

Dum p t he ent ire current cont ent s of t he t able int o a one or m ore SAS dat a set. Not e t hat for t he key s t o dum ped, t hey m ust be defined using t he DefineDat a m et hod. I f t he t able has been loaded in order, it will be dum ped also in order. More inform at ion about t he m et hod will be provided lat er on. D a t a St e p Obj e ct D ot Syn t a x As we have seen, in order t o call a m et hod, we only have t o specify it s nam e preceded by t he nam e of t he obj ect followed b y a period, such as: hh.

DefineKey hh. Find hh.

SAS Hash Object Programming Made Easy

Replace hh. First hh. Output and so on. Not e t hat t he obj ect dot synt ax is one of very few t hings t he Dat a st ep com piler knows abou t DSCI. The com piler re cognizes t he synt ax, and it react s harshly if t he dot synt ax is present , but t he obj ect t o which it is apparent ly applied is absent. However, as t heir num ber grows, we h ad bet t er get used t o t he obj ect dot sy nt ax really soon, part icularly t hose dinosaurs am ong us who have not exact ly learned t his kind of t ongue in t he kindergart en An inquiring m ind would like t o know: What is inside?

Not t hat we really need t he gory det ails of t he underlying code, but it is inst ruct ive t o know on which principles t he design of t he int ernal SAS t able is based in general. A good driver is always curious what is under t he hood. Well, in general, hashing is hashing is hashing - which m eans t hat it is always a t wo- st aged process: 1 Hashing a key t o it s bucket 2 resolving collisions wit hin each bucket. Hand- coded hashing cannot rely on t he sim ple st raight separat e chaining because of t he inabilit y t o dynam ically allocat e m em ory one ent ry at a t im e, while reserving it in advance could result in unreasonable wast e of m em ory.

Since t he hash and hit er obj ect s are coded in t he underlying soft ware, t his rest rict ion no longer exist s, and so separ at e chaining is perhaps t he m ost logical way t o go. I t s concret e im plem ent at ion, however, has som ewhat deviat ed from t he classic schem e of connect ing keys wit hin each node int o a link list. I nst ead, each new key hashing t o a bucket is insert ed int o it s binary t ree.

AVL t rees are binary t rees populat ed by such a m echanism t hat on t he average guarant ees t heir O log N search behavior regardless of t he dist ribut ion of t he key values. First , a m yst erious int ernal hash funct ion m aps t he key, whet her is it sim ple or com posit e, t o som e bucket. The t ree in t he bucket is searched for KEY. I f it is not t here, t he key and it s sat ellit e dat a are insert ed in t he t ree. Just how fast all t his occurs depends on t he speed of search.

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However, binary searching t he 16 keys in t he AVL t ree requires only about 5 keys com parisons. I f we had 10 m illion keys, it would require about 7 com parisons, which pract ically m akes alm ost no difference. Thus, by choosing HASHEXP j udiciously, it is t hus possible t o t weak t he hash t able perform ance t o som e degr ee and depending on t he purpose. From our prelim inary t est ing, we have not been able t o not ice any m em ory usage penalt y exact ed by going t o t he m ax, all t he m ore t hat as of t his writ ing, t he Dat a st ep does not seem t o report m em ory used by an obj ect called t hrough t he DSCI.

At least , experim ent s wit h int ent ionally large hash t ables show t hat t he m em ory usage report ed in t he log is definit ely m uch sm aller t han t he hash t able m ust have occupied, alt hough it was evident from perform ance t hat t he t able is com plet ely m em ory- resident , and t he soft ware ot herwise has no problem handling it. On t he ot her hand, if t here is no need for it erat or processing, it is bet t er t o leave t he t able com plet ely it erat or- free by not specifying a non- zero ORDERED opt ion.

Maint aining an it erat or over a hash t able obviously requires cert ain overhead.

There are a num ber of com m on sit uat ions in dat a processing when t he inform at ion needed t o size a dat a st ruct ure becom es available only at execut ion t im e. SAS program m ers usually solve such problem s by pre- processing dat a, eit her i.

As m ore program m ers becom e fam iliar wit h t he possibilit ies t his dynam ic st ruct ure offers, t hey will be able t o avoid resort ing t o m any old kludges. Delete ; This will elim inat e t he t able from m em ory for good, but not it s it erat or!

Delete ; I f at som e point of a Dat a st ep program t here is a need t o start building t he sam e t able from scrat ch again, rem em ber t hat t he com piler m ust see only a single definit ion of t he sam e t able by t he sam e t oken as it m ust see only a single declarat ion of t he sam e array and if t he rule is broken, it will issue t he sam e error m essage, e.

DefineKey 'k' ; 26 hh. DefineData 'sat' ; 27 hh. DefineDone ; 28 29 hh. DefineKey 'k' ; 49 hh. DefineData 'sat' ; 50 hh. DefineData 'sat' ; hh. This way, t he declarat ion is easily placed ahead of any obj ect references, and t he com piler sees t he declarat ion j ust once.

I n a m om ent , we will see an exam ple doing exact ly t hat. Suppose t hat during DATA st ep processing, we need t o m em orize cert ain key elem ent s and t heir at t ribut es on t he fly, and at different point s in t he program , answer t he following: 1. Has t he current key already been used before? I f it is new, how t o insert it in t he t able, along wit h it s at t ribut e, in such a way t hat t he quest ion 1 could be answered as fast as possible in t he fut ure?

Given a key, how t o rapidly updat e it s sat ellit e? I f t he key is no longer needed, how t o delet e it? Exam ples showing how key- indexing can be used for t his kind of t ask are given in [ 1]. Here we will t ake an opport unit y t o show how t he hash obj ect can help an unsuspect ing program m er. Sim ple! I n ot her words, for t he sam ple dat a set , we need t o produce t he following out put : id transid sum 1 15 1 12 97 1 11 66 3 13 3 11 3 12 Usually, t his is a 2- st ep pr ocess, eit her in t he foreground or behind t he scenes SQL.

Cont rol is t hen passed t o t he t op of t he im plied Dat a st ep loop where it encount ers t he t able definit ion. I t causes t he old t able and it erat or t o be dropped, and new ones - defined. I f t he file has not run out of records, t he out er Do- Unt il loop begins t o process t he next I D, and so on. However, it has one not able short com ing: I t does not operat e quit e well when t he cardinalit y of it s cat egorical variables is high.

The r esult is poor m em ory ut ilizat ion and slow run t im es. The usual way of m it igat ing t his behavior is t o sort t he input beforehand and use t he BY st at em ent inst ead of t he CLASS st at em ent. This usually allows running t he j ob wit hout running out of m em ory, but t he pace is even slower - because now, SUMMARY has t o reallocat e it s t ree for each new incom ing BY- group.

The hash obj ect also holds dat a in m em ory and has no problem handling any com posit e key, but it need not carry all t he baggage SUMMARY does. So, if t he only purpose is, say, NWAY sum m arizat ion, hash m ay do it m uch m ore econom ically. Let us check it out by first creat ing a sam ple file wit h 1 m illion dist inct keys and 3- 4 obser vat ions per key, t hen sum m arizing NUM wit hin each group and com paring t he run- t im e st at s.

INPUT has observations and 3 variables. And at t hat , t he full pot ent ial of t he hash m et hod has not been achieved yet. Due t o t he very nat ure of t he process, for each incom ing key, SUM is first has t o be dum ped int o it s host variable, t hen increm ent ed, and finally reinsert ed int o t he t able.

For some other pages or areas e. We have talked a bit about certain other aspects like point release workflow, the build time of the website, team memberships and governance. In general the sprint has shown that for most of the discussed topics the migration to git as VCS and the existence of Salsa is a huge step forward for the usability and attractiveness for contributors of the webwml repository.

The core webteam is happy that the sprint has also attracted new people to jump in and which are also members of the webteam now.

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We welcome Thomas Lange and Carsten Schoenert in our team! Finally, we have passed time together to socialize and knowing each other better, and got very motivated to continue working on the web. The participants would like to thank all donors to the Debian project who helped to cover a large part of our expenses.

So I switched back to the same version as the one DoroWu chose, and this time no more disconnections. I forced myself to have at least spoonfulls at one level to see if it will stay and also that I needed to have some food in the stomach. While the night was not peaceful, it was much more peaceful than at the Camp.

I probably woke up handful of times but each time looking at the lake just filled me with peace. At times, I wished I was all better so could have spend the whole night just seeing the lake. However, I have had some progress recently in organizing my time. Regarding the writing habit, I will try a more minimalist approach to improve my frequency by writing short texts with some quick notes or tips that are useful to others and myself in the future.

SAS Hash Object Programming Made Easy

This is my first post where I apply this approach. It has a little tip about how to initialize your Ruby objects passing named arguments with a Hash.

Besides the support for initializing objects with a hash, the ActiveModel::Model module adds other behaviors to your classes that you may not be interested in, such as model name introspections, conversions, translations and validations. However, if you are not using Rails, but still want to initialize your objects with Hashes, you can create a generic module with the single purpose of implementing such behavior and include it into your classes.

I got an enclosure to go with it because I was enthusiastic and optimistic about my ability to get things all set up.

My plan was to take the 1T disks I had in the storage server I had been using before, but which had since failed and to put them into this new enclosure. Unfortunately, when I attached the disks to the controller, none of them worked and I gave up frustrated and disillusioned for a good long time. Last week was spring break, and I took a few days off from work to hang out with my girls.

The lsscsi command showed nothing. But the lspci command showed the controller, and I started digging through documentation to figure out what might be wrong. I eventually stumbled upon a firmware flashing ISO disk image on the Broadcom site.

Broadcom apparently downloadd LSI not too long ago and is now responsible for managing documentation and downloads for the legacy devices, of which I am now a proud owner. I had to modify the syslinux. And for some reason, unetbootin replaced the filename of the disk image from which freedos was supposed to boot with something useless.

In any case, after corrections, the entry in syslinux.

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