How to Use INPUT and PUT Functions for Data Conversion in SAS

In the world of data processing, especially in SAS programming, data conversion is a fundamental task. Properly converting data types ensures accurate analysis and reliable outcomes. Two essential functions in SAS for data conversion are the INPUT and PUT functions. This article will provide a comprehensive guide to using these functions effectively, including their syntax, examples, practical applications, and FAQs to clarify common queries.

Focus Keyphrase: INPUT and PUT Functions

Our focus keyphrase, “INPUT and PUT Functions,” will guide our exploration of these vital tools for data conversion in SAS.

Understanding Data Conversion in SAS

Data conversion in SAS is the process of transforming one data type into another. This is crucial because SAS can work with various data types, such as character and numeric. The INPUT function is used to convert character data to numeric, while the PUT function converts numeric data to character. Understanding how to use these functions effectively can enhance your data analysis capabilities.

The INPUT Function

Overview of the INPUT Function

The INPUT function converts character strings to numeric values based on specified formats. This function is particularly useful when dealing with data imported from external sources, where numbers may be stored as text.

Syntax of the INPUT Function

INPUT(source, informat)

• source: The character string you want to convert.
• informat: The format used for the conversion (e.g., 8., MMDDYY10.).

Example of the INPUT Function

Consider a scenario where you have a dataset with numeric values stored as character strings:

DATA sales_data;
    INPUT Sales_Amount $;
    DATALINES;
1000
2000
3000
;
RUN;

DATA numeric_sales;
    SET sales_data;
    Numeric_Sales_Amount = INPUT(Sales_Amount, 8.);
RUN;

PROC PRINT DATA=numeric_sales;
RUN;

In this example, the INPUT function converts the Sales_Amount character string into a numeric value stored in Numeric_Sales_Amount.

Practical Applications of the INPUT Function

1. Importing Data: When importing data from Excel or CSV files, numeric values may be stored as text. The INPUT function helps convert these to numeric types for analysis.
2. Data Cleaning: Use the INPUT function to clean datasets, ensuring that all numeric fields are correctly formatted.
3. Date Conversions: The INPUT function can convert date strings into SAS date values, facilitating date-related analyses.

The PUT Function

Overview of the PUT Function

The PUT function performs the opposite of the INPUT function, converting numeric values to character strings based on specified formats. This function is particularly useful for preparing data for reports or export.

Syntax of the PUT Function

PUT(source, format)

• source: The numeric value you want to convert.
• format: The format used for the conversion (e.g., COMMA10., DATE9.).

Example of the PUT Function

Suppose you have a dataset of numeric sales amounts that you want to convert to character format for reporting:

DATA numeric_sales;
    INPUT Numeric_Sales_Amount;
    DATALINES;
1000
2000
3000
;
RUN;

DATA character_sales;
    SET numeric_sales;
    Sales_Amount_Char = PUT(Numeric_Sales_Amount, COMMA10.);
RUN;

PROC PRINT DATA=character_sales;
RUN;

In this case, the PUT function converts the Numeric_Sales_Amount into a character string formatted with commas.

Practical Applications of the PUT Function

1. Generating Reports: Use the PUT function to create formatted strings for easier readability in reports.
2. Exporting Data: When exporting data to text files or other formats, converting numeric data to character format may be necessary.
3. Data Preparation: The PUT function can prepare numeric variables for concatenation with character variables in data processing tasks.

Combining INPUT and PUT Functions

In many cases, you may find yourself using both the INPUT and PUT functions within the same data step, especially when working with datasets that require extensive cleaning and formatting.

Example of Combining Functions

DATA combined_example;
    INPUT Sales_Amount $;
    DATALINES;
1000
2000
3000
;
RUN;

DATA final_data;
    SET combined_example;
    Numeric_Sales = INPUT(Sales_Amount, 8.);
    Sales_Formatted = PUT(Numeric_Sales, COMMA10.);
RUN;

PROC PRINT DATA=final_data;
RUN;

In this example, we first convert the Sales_Amount from character to numeric using the INPUT function and then reformat it to a character string with commas using the PUT function.

Important Considerations

1. Informat and Format: Choose the correct informat for the INPUT function and the appropriate format for the PUT function to avoid conversion errors.
2. Data Types: Ensure you understand the data types of your variables to use these functions correctly.
3. Performance: Be mindful of performance when processing large datasets, as excessive conversions may slow down processing time.

FAQs About INPUT and PUT Functions

1. What is the difference between INPUT and PUT functions?

• INPUT converts character strings to numeric values, while PUT converts numeric values to character strings.

1. How do I choose the correct informat for the INPUT function?

• Select an informat that matches the format of your source data (e.g., MMDDYY10. for date strings).

1. Can I use INPUT to convert date strings to SAS date values?

• Yes, you can use the INPUT function with appropriate date informats to convert date strings to SAS date values.

1. Is the PUT function case-sensitive?

• No, the PUT function itself is not case-sensitive; however, the formats it uses may be.

1. Can I use multiple formats with the INPUT or PUT functions?

• You can only use one informat or format at a time, but you can chain multiple conversions within a single data step.

1. What happens if the INPUT function encounters non-numeric characters?

• The INPUT function will return a missing value if it encounters non-numeric characters that it cannot convert.

1. Can I convert character variables with leading zeros using the INPUT function?

• Yes, you can convert character variables with leading zeros to numeric values, but the leading zeros will be lost in the conversion.

1. Where can I find documentation for SAS functions?

• The official SAS Documentation provides comprehensive information about all SAS functions, including INPUT and PUT.

1. How can I convert numeric values to formatted strings for reporting?

• Use the PUT function with the appropriate format to generate formatted strings from numeric values for reporting purposes.

1. Are there any performance considerations when using these functions?
   • Yes, when working with large datasets, excessive data conversions can slow down processing times. Optimize your data steps where possible.

External Resources for Further Learning

• SAS Official Documentation: A comprehensive resource for understanding SAS functions, including INPUT and PUT.
• SAS Support Communities: A platform for discussing and sharing knowledge about SAS programming.
• SAS Training Resources: Offers official SAS training courses to enhance your programming skills.

Conclusion

The INPUT and PUT functions are invaluable tools for SAS professionals working with data conversion. Mastering these functions allows for seamless handling of character and numeric data, enabling accurate analysis and reporting. By applying these functions effectively, you can improve your data processing capabilities and ensure your analyses yield reliable results. Whether you’re cleaning datasets or preparing reports, understanding how to use INPUT and PUT will enhance your proficiency in SAS programming. Happy coding!