In SAS, changing the data type of a variable is a common task when working with datasets. Whether you need to convert a character variable to numeric or vice versa, SAS provides several options to accomplish this. In this tutorial, we will explore different methods to change the data type in SAS.
Using the INPUT Function
If you have a character variable and want to convert it to numeric, you can use the INPUT function in SAS. The INPUT function reads the value of a character variable and converts it into a numeric value based on the specified informat.
To change the data type using the INPUT function, you need to create a new numeric variable and assign it the converted values from the character variable. Here’s an example:
data new_dataset;
set original_dataset;
new_numeric_variable = input(character_variable, best.);
run;
In this example, we create a new dataset called new_dataset which contains all observations from the original dataset. The new_numeric_variable is created as a numeric variable using the BEST. informat.
Casting Character Variable as Numeric Using PUT Statement
An alternative approach is to use the PUT statement in SAS. The PUT statement is typically used to convert numeric values into character values, but by reversing its usage, we can cast a character variable as numeric.
To change the data type using the PUT statement, you need to create a new numeric variable and assign it with converted values using the PUT() function. Here’s an example:
data new_dataset;
set original_dataset;
new_numeric_variable = put(character_variable, best.);
run;
Converting Numeric Variable to Character Using PUT Statement
If you have a numeric variable and want to convert it to character, you can use the PUT statement in SAS. The PUT statement converts the numeric value into a character value based on the specified format.
To change the data type using the PUT statement, you need to create a new character variable and assign it with converted values using the PUT() function. Here’s an example:
data new_dataset;
set original_dataset;
new_character_variable = put(numeric_variable, dollar10.);
run;
In this example, we create a new dataset called new_dataset, which contains all observations from the original dataset. The new_character_variable is created as a character variable using the DOLLAR10. format.
The CATS Function for Concatenating Variables
Sometimes you may need to concatenate multiple variables into one character variable. SAS provides the CATS function to concatenate variables without any separators.
To change data type and concatenate variables using the CATS function, you need to create a new character variable and assign it with concatenated values using the CATS() function. Here’s an example:
data new_dataset;
set original_dataset;
new_character_variable = cats(variable1, variable2, variable3);
run;
In this example, we create a new dataset called new_dataset which contains all observations from the original dataset. The new_character_variable is created as a character variable by concatenating variable1, variable2, and variable3.
Conclusion
In SAS, changing the data type of a variable can be achieved using various methods such as the INPUT function, PUT statement, and concatenation using the CATS function. These techniques allow you to manipulate your data to match your analysis requirements. Remember to consider any potential loss of information or unintended consequences when changing data types.
In summary:
- The INPUT function converts character variables to numeric.
- The PUT statement can be used to convert character variables to numeric or vice versa.
- The CATS function concatenates variables into a single character variable.
I hope this tutorial helps you understand how to change data types in SAS effectively!