Accessing data, creating data structures, managing data. This paper presents a number of examples to demonstrate how to take advantage of the % do loop to build sas statements dynamically. Again, we run a regression model separately for each of the four race categories in. A sas macro to automate importing excel worksheets into. Extracting data from pdf files nat wooding, dominion virginia power, richmond, virginia abstract the adobe portable document file pdf format has become a popular means of producing documents for use on other computers when the author cannot be certain of the software available on the other machines. I end up with files such as main file, temp1, temp2, temp3, temp4, temp5, temp6, temp7, temp8 and temp9. All of the files have the same data step, so im trying to write a do while loop to import all the files. If you use a macro loop to do this computation, it will take a long time for all the reasons stated in the article the slow way or the by way. One way to overcome the inefficient use of time, manpower, and computer processing is to use sas arrays and do loops. Sas will then progress on to the code you typically use to process the file. Carpenter california occidental consultants, anchorage, ak abstract do loops and array statements are common tools in the data step.
Do while loops continue executing while the condition you have specified remains true. An easy way to run thousands of regressions in sas the. Learn how to use doloop, dowhile and dountil in sas. So the problem is that sas does not treat subsequent values of i as numbers but as text. A vba macro to convert all rtf files within one folder into. Sas enhancements, above, the whilecondition is evaluated at the top of the loop, test2, line 5, whereas the untilcondition is evalu ated at the bottom of the loop, test5, line 10. I want all regression outputs to be in pdf file 1, all print outputs in pdf file 2 and all plot outputs in pdf file 3.
I have an excel file in which i have a macro that creates a series of pdf files via the activesheet. Use the %do statement to loop through the entire directory based on the number of members returned from the dnum function. Lets say you have a series of sas data sets class1 class10 that contain students math scores and you want to calculate the average scores for each of the ten classes. Running sas code on multiple files with do loop and a macro i am very new to sas and have received my first work assignment. The iterative %do defines and increments a macro variable. Data statement sas statements do statement iterated sas statements end statement sas statements run statement do loop processing you can use do loops to perform repetitive calculations. I know gtl at least ive heard of it, not that i have great experience in this area but i agree that for this example might be a bit overkill i would rather do it manually i looked at your code and i see that you used the put function. Working with finance data in sas justin mccrary professor of law and dlab director, uc berkeley faculty research associate, nber dlab workshop tuesday, january 27, 2015. Exporting to multiple pdf files in a loop by appen. If i do it the way in the code above, only the last loops results are saved in each of the files, because every iteration overwrites the previous one, instead of appending to the bottom of it.
In this sas tutorial, we will explain how you can learn sas programming online on your own. The first statement in a function is executed first, followed by the second, and so on. We did not have success opening these files in other browsers. The sas iml language is a matrixvector language, so statements that operate on a few long vectors run much faster than equivalent statements that involve many scalar quantities. Do loop processing do loop processing statements within a do loop execute for a specific number of iterations or until a specific condition stops the loop.
I have some advice on using do loops in sasiml language. This paper presents a number of examples to demonstrate how to take advantage of the %do loop to build sas statements dynamically. From my research, i believe i need a macro with a do loop that will run this search for all of the files. An alternative way to analyze those regression models is to transpose the data to long form and use a bygroup analysis. Vba macro will enable excel to loop through all nonblank cells in column a except for cell a1 until all files are converted. You can aggregate the statistics by using proc append or the data step. A macro for reading multiple text files debbie miller, national park service, denver, co abstract most of us have to exchange data at some time or another with others who do not use the sas system, and therefore cannot use or send sas data sets. Importing data files that are not in sas format into sas and compiling them for. Mar 30, 2020 dofile is also a function used when compiling and executing lua programming code, but it isnt related to the. In the case of these files, i could not used a macro. Running sas code on multiple files with do loop and a macro. Depending on the problem you are trying to solve, one of statas looping commands. Beaverton, or portland, or abstract the use of multiple set statements in a data step is little known and often misunderstood. A vba macro to convert all rtf files within one folder.
When used within nested do loops, exit do transfers control out of the. It includes many base and advanced tutorials which would help you to get started with sas and you will acquire knowledge of data exploration and manipulation, predictive modeling using sas along with some scenario based examples for practice. A sas array is a set of variables of the same type, called elements of the array, that you want to perform the same operation on. The statements in a do until loop are always executed at least once, but the statements in a do while loop will not execute even once if the do while expression is false. You can reshape the data using proc transpose or reshape the data in a data step. More advanced macro techniques after mastering the basic techniques discussed earlier in this chapter, you may want to learn some more advanced macro techniques. What is the best way to loop through each file and create one big file or a dataset per file to get the total number of rows across all files. Example 3 nested do loops when a do loop is iterating within another do loop, it is known as a nested do loop. A macro to produce a sas data set containing the list of. Multipage pdf documents can be displayed as a presentation, similar to a microsoft powerpoint, where the pdf automatically progresses each page as well as being able to loop the presentation. List all files within a directory including subdirectories tree level 3. Only when this file exists, excel will convert it to pdf files and place the newly created pdf file into folder d. An easy way to run thousands of regressions in sas the do loop.
Reshaping data wide to long using a data step sas learning. The difference between while and until is obfuscated by their placement at the top of the loop construct. It can also be used to dynamically build a series of data steps or proc steps. List all files within a directory including subdirectories. Top 50 sas interview questions for 2020 sas training edureka. This macro will run a do loop creating state twodigit abbreviations, which will allow a simple way to read the summary files into sas for all geographies. The outest option saves the parameter estimates in a data set. Use the rank function to return the position of a character in the ascii or ebcdic collating sequence. Sep 07, 2011 today is the first anniversary of this blog, which is named the do loop, so it seems appropriate to blog about do loops in sas.
I am very new to sas and have received my first work assignment. The iterative %do is very similar to the do statement used in the data step, but it is not confined to the data step. Tasks 1, 2 and 3 each produces some output i would like to save in 3 separate pdf files. Nested do loops are easier to understand with a simple example. The program communicates what you want to do and is written using the sas language. Sas do index loop this do index loop uses a index variable for its start and end value. I have a list of 17 flat files that im trying to import into different data sets. The result is that a do until loop will always execute at least. Learning by doing is the best way to master a programming language.
The main difference between the do while and do until loop is that the do until expression is evaluated at the bottom of the loop while the do while is evaluated at the top of the loop. How to increment a macro do loop by a noninteger value. To do this you first need to create your standard pdf document and then configure adobe reader to progress automatically and loop when in full screen mode. A beginners guide to arrays and do loops sas institute.
There are two forms of conditional do loops, do until loops and do while loops. In previous examples, the % do loop is used to generate single sas statements. Sas tutorial for beginners to advanced practical guide. The do loop because arrays are easily referenced with an index value, they are very often used with a do loop. The iterative % do is very similar to the do statement used in the data step, but it is not confined to the data step.
Do you know that the sas certified specialist exam now requires you to write and execute code in the exam. But when you want the same set of statements to be executed again and again, we need the help of loops. Generating repetitive pieces of text using %do loops. The first type of do loop uses a list either numeric or character and the loop is executed once for each value in the list specified in the do loop. Import all csv files that exist within a directory. One use of exit do is to test for a condition that could cause an endless loop, which is a loop that could run a large or even infinite number of times. The following will illustrate how to reshape data from wide to long using the data step. You can include any number of exit do statements anywhere in a doloop. Together they allow us to iteratively process large amounts of data with a minimum amount of code. Generating repetitive pieces of text using % do loops. If you are used to conditionally processing statements in a doloop in sas, there is no real substitute for that in stata. Sas loops you may encounter situations, when a block of code needs to be executed several number of times. Ill describe looping in the sas data step and compare it with looping in the sas iml language. With sas, you use statements to write a series of instructions called a sas program.
The until expression is evaluated after the statements in the do loop have executed, and the while expression is evaluated before the statements in the do loop have executed. Extracting data from pdf files nat wooding, dominion virginia power, richmond, virginia. A powerful technique for combining and aggregating complex data renu gehring sas instructor health care analyst acecube, llp careoregon, inc. What sas statements would you code to read an external raw data file to a data step. Do until loops continue executing until the condition you have specified becomes true. Proc import combined with % do loop to read in the data from multiple excel worksheets. How can i generate pdf and html files for my sas output. The iterative % do defines and increments a macro variable. Looping through files in a directory sas support communities.
Each time a valid two digit state abbreviation is created, the macro %allseqs is run with the two digit state abbreviation. Sas macro do loop import multiple flat files stack overflow. The sas statements are repeatedly executed until the final value of the index variable is. Mar 22, 20 multipage pdf documents can be displayed as a presentation, similar to a microsoft powerpoint, where the pdf automatically progresses each page as well as being able to loop the presentation. Running sas code on multiple files with do loop and a. Sep 07, 2011 i have some advice on using do loops in sas iml language. The other type of do loops that you can run in a sas data step are conditional do loops. In this example, we will create 3 records for each value of id, where id is a number from 1 to 4.
Arrays are used in the sas data step to reduce the amount of code that has to be written to accomplish these types of tasks. Creating sas data sets from input files that contain raw data external files creating new sas data sets from existing ones by subsetting, merging, modifying, and updating existing sas data sets analyzing, manipulating, or presenting your data computing the values for new variables report writing, or writing files to disk. I then wrote a simple loop and put statement routine that created and stored a years worth of macro calls. A macro to produce a sas data set containing the list of file names found in the requested windows or unix directory mike goulding, experis, portage, mi, usa abstract clinical programmers often need to perform a particular process for each file that exists in a specific directory, on windows or unix. The %sysfunc function is needed to use sas functions within the macro facility. What i would like to do now is combine these files into a single file with the same name as the main file. Today is the first anniversary of this blog, which is named the do loop, so it seems appropriate to blog about do loops in sas. Fortunately, there is a more efficient alternative. Arrays and do over loops are a way of programming more. You can join our sas base certification training program free of charge. Dec 05, 2019 use the rank function to return the position of a character in the ascii or ebcdic collating sequence.
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