Using arrays, the vname function and scan(), we're able to compare all numeric variables in have1 with all numeric variables in have2. Remember that underscore we added to the second dataset's variables? We're going to ignore that. Next, we'll take a double-loop approach where we'll check every variable against each renamed variable. We can place this in a rename=() dataset option. This will make it easy for us to compare later. We've added an underscore to all the variable names. If we look at &rename, we'll see we've created some code to help us rename all of the variables in the second dataset: We'll also generate code that renames the variables in the second dataset: proc sql noprint We'll need to do this logically so that we can easily compare names.įirst, we'll create some code that gets all the variables from each dataset. The strategy here will be to rename the columns in one dataset and check them against the other dataset. The main problem we have is that SAS will automatically overwrite data if the columns have the exact same name. There is probably a much more elegant solution with IML or even with base SAS. Hopefully this article has been useful for you to learn how to combine multiple datasets vertically in SAS.Here is one solution that uses base SAS functions. proc append base=dataset1 data=dataset2 force If the variables in the two datasets aren’t the same, you can pass FORCE to force PROC APPEND to append the datasets. One other consideration is that with PROC APPEND, by default, the variables MUST be the same. The resulting dataset “dataset1” is shown below. Instead, you are appending the second dataset to the base dataset.īelow is an example of how you can append datasets with PROC APPEND in SAS using the same datasets as the first example from above. With PROC APPEND, you don’t create a new dataset. The first argument is the dataset you want to append to, and the second argument is the dataset you want to append. To use PROC APPEND, you pass two arguments. You can also use PROC APPEND to combine two datasets and append one dataset to another. 3 Using PROC APPEND to Combine Datasets Vertically in SAS Second, if you have columns with the same name and different data types, then you will get an error.īelow is an example of the output in SAS of combining datasets with “set” when you have different variables. When you go to combine multiple SAS datasets in a SAS Data Step and you have different variables, there are a few different things to understand.įirst, if you have different columns, then in the newly created dataset you will have missing values for the records where the column didn’t exist in the input dataset. numģ Appending SAS Datasets in Data Step with Different Variables and Data Types The resulting dataset “new” is shown below. With this method, you can stack as many datasets as you want and append many datasets on top of one another.īelow is a simple example of how you can append two SAS datasets in a SAS Data Step. “Setting” datasets stacks the given datasets vertically and allows you to create a new dataset. This handout illustrates combining data sets vertically by adding more cases (stacking or appending data sets) and combining data sets horizontally by adding new variables (merging data sets). The easiest way to combine datasets vertically is by “setting” datasets with the set statement. There are many ways that SAS data sets can be combined. Various operations, such as merging and appending, allow us to create new datasets from existing datasets. When working with data in SAS, the ability to create new datasets is valuable. You can also use PROC APPEND to append a dataset at the end of another dataset. To combine datasets vertically in SAS, the easiest way is to “set” the datasets in a SAS data step.
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