Length SAS Function: Tips and Examples

The LENGTH SAS function is used to determine the length of character strings in SAS programming. It returns the length of the string in characters, excluding trailing blanks, and is helpful in data manipulation, analysis, and reporting. The LENGTH function is often used in conjunction with other SAS functions to perform a variety of tasks.

Length vs. LengthM Function

It’s important to distinguish between the LENGTH function and LENGTHM function in SAS programming. While the LENGTH function returns the length of a character string in characters, the LENGTHM function returns the amount of memory in bytes allocated for the string. In other words, the LENGTHM function returns the number of bytes allocated for the variable, including the trailing blanks, while the LENGTH function returns only the number of characters.

It’s worth noting that the value returned by LENGTH is always less than or equal to the value returned by LENGTHM since trailing blanks are excluded from LENGTH. This means that the LENGTH function is more useful when working with character data, while LENGTHM is more commonly used with binary data or strings that contain complex characters like Unicode.

Usage and Examples

The LENGTH function can be used in a variety of ways in SAS programming. One common use is to identify the length of character strings and then format them appropriately for data analysis or reporting. For example, if a dataset contains character fields with varying lengths, the LENGTH function can be used to standardize the data, making it easier to analyze.

Consider the following example:

In the example above, the LENGTH function is used to determine the length of four character strings in a SAS dataset. These values are then stored in separate variables for further analysis and processing.

Conclusion

Overall, the LENGTH SAS function is an essential tool for any SAS programmer working with character data. It allows for the easy identification of string lengths and helps to ensure that data is standardized and processed effectively. By understanding the basics of the LENGTH function and how it works, SAS programmers can take full advantage of its functionality and improve their data analysis and reporting capabilities.

What is the Length SAS Function?

The Length SAS function is a function used in SAS programming to determine the length of a character value or string, and does not count trailing blanks. Its main purpose is to exclude any trailing spaces and provides the length of the string in characters. It is denoted by the keyword “LENGTH” in SAS.

How does the Length SAS Function work?

The Length SAS function takes a character or text string as an argument and returns the length of the string. It counts the actual number of characters in a string and ignores any trailing spaces at the end of the string. One key thing to note is that the function is not case sensitive, meaning it will count upper and lower case characters as separate characters. Additionally, if no arguments are supplied, the function will return a value of 1.

What is the difference between LENGTH and LENGTHM?

The LENGTH function and LENGTHM function are both used to determine the length of a character value but differ in their approach to measuring it. LENGTH returns the length of a character string in characters, excluding trailing blanks, while LENGTHM returns the amount of memory in bytes allocated for the character string. In essence, LENGTH provides a count of the number of characters in a string, while LENGTHM gives the total memory in bytes consumed by that string. Since LENGTH counts only the number of characters, it is less than or equal to the value returned by LENGTHM, which includes characters and other memory management overheads.

How is the Length SAS Function used in programming?

The Length SAS function is an essential tool used by programmers in SAS programming to manage the length of character strings within their programs. It is commonly used in data manipulation and transformation programs where data values are read, processed, and written to new files. The LENGTH function is used to ensure that the resulting files do not exceed the allowed space for storage while ensuring that the data is precise and remains consistent with the data type expected. Additionally, it can be useful in cases where SAS is exporting data as an ASCII text file, as many applications expect fixed-format text files with delimited entries of equal length.

How to Find the Length of a Character Variable using Length SAS Function

To determine the length of a character value, we can use the Length SAS Function. This function returns the length of the string in characters and excludes any trailing blanks. Let’s explore step-by-step how we can use this function:

Step 1: Open SAS Program

First, open your SAS Program and open the file for which you want to determine the length of a character variable.

Step 2: Write the LENGTH SAS Function in Code

To use the LENGTH SAS function, write it in your SAS code. You can use it in the DATA step or a PROC step. For example:data newdataset;
set olddataset;
length new_variable $10;
new_variable = old_variable;
variable_length = length(old_variable);

Step 3: Understand the LENGTH function

The LENGTH function returns the length of a character string in characters, excluding trailing blanks. If the argument is null, it returns a value of 1. For example, if the argument for the LENGTH function is a single space, it still returns a value of 1.

Step 4: Understand the LENGTHM function

The LENGTHM function returns the number of bytes allocated for a character string. It is important to note that this function returns a value greater than or equal to the value returned by LENGTH.

Step 5: Assign the LENGTH to a New Variable

After executing the LENGTH SAS function, the length of the character variable will be assigned to a new variable. In the example above, the new variable is “variable_length”.

Step 6: Run the SAS Program

Finally, run the SAS program and view the result to see the length of the character variable.

By following these six steps, we can easily determine the length of a character variable using the LENGTH SAS function. Remember that this function only counts the number of characters and excludes any trailing blanks.

How to Find the Length of a Numeric Variable using Length SAS Function

To find the length of a numeric variable using the Length SAS Function, follow these steps:

1. Convert the numeric value into a character value using the PUT function.
2. If necessary, remove any unwanted characters like dollar signs or periods.
3. Apply the Length SAS Function to calculate the length of the character string.

Let’s take an example of how to use the Length SAS function. Suppose we have a numeric value like 12345. We can convert this numeric value into a character string using the PUT function like this:

In the above code, we first defined a dataset called “example”, then we defined a numeric value called “x” which is equal to 12345. Then we converted this numeric value into a character value called “y” using the PUT function with a format of 5. Finally, we applied the Length SAS function to calculate the length of this character string and stored this value in a variable called “z”.

After running this code, the result of “z” would be 5 because the character string “12345” is 5 characters long.

Default Length of a Variable in SAS

When defining a new variable in SAS, it will automatically be assigned a default length of 8 bytes. This means that for numeric variables, it can hold up to 16 digits, while character variables can hold up to 8 characters. However, it is important to note that the default length can vary depending on the system configuration and SAS version.

If you need to store more than 8 characters in a character variable or more than 16 digits in a numeric variable, you can change its length by using a LENGTH statement. Keep in mind that increasing the length of a variable can also increase its memory usage, so it is important to balance your needs with system resources.

How to Change the Length of a Variable in SAS

The LENGTH function in SAS can be used to determine the length of a character value or string, and it does not count any trailing blanks. It is important to note that if an argument is null, LENGTH will return a value of 1. On the other hand, LENGTHM is used to return the amount of memory in bytes that is allocated for the character string.

To change the length of a variable in SAS, you can use the LENGTH statement. For numeric variables, you should convert the numeric value into a character value using the PUT function before it can be modified. Afterward, you can remove unwanted characters such as dollar signs, periods, among others. You can then calculate the length using the LENGTH function.

It is also essential to note that the maximum length of any character variable in SAS is 32,767 bytes. For character variables, the LENGTH statement consists of three steps which involve the LENGTH keyword, the name of the variable to be changed, then followed by the desired length which is denoted by a dollar sign.

For instance, consider the scenario where you want to change the length of a variable named ‘Name’ from a default length to 15. The LENGTH statement would appear as follows: LENGTH Name $15.

Examples of changing the length of a variable in SAS include:

In the example above, the LENGTH statement is used to change the length of the ‘lastname’ variable from its default value to a shorter value of ‘7’, which is followed by a period. As such, the new variable ‘lastname’ will have a shorter length compared to the original variable.

Maximum Length of a Variable in SAS

The maximum length of any character variable in SAS is 32,767 bytes. This is an essential fact to remember for SAS programmers who deal with character variables. The LENGTH function in SAS can help you determine the length of a character value, and it does not count trailing blanks. Additionally, the LENGTHM function can return the amount of memory in bytes that is allocated for a character string. However, it is important to note that LENGTH always returns a value that is less than or equal to the value returned by LENGTHM.

If you need to change the length of a variable in SAS, a subsequent LENGTH statement can help you do so for numeric variables. For character variables, the LENGTH statement consists of three steps: the LENGTH keyword, the name(s) of the variable(s) that you want to change, and a dollar sign followed by the desired length. It is important to remember that the maximum length of a variable in SAS is 32 bytes.

Overall, understanding the maximum length of a variable in SAS is crucial for SAS programmers to ensure that their character variables operate efficiently and effectively.

Examples of Using Length SAS Function

The Length SAS function is utilized in various ways across different SAS applications. Here are some examples of how the Length SAS function can be used:

Calculating the Length of a Character Variable

One of the main uses of the Length SAS function is to determine the length of a character variable. This is important when working with large datasets and when storage space is a concern. For instance, to calculate the length of a string excluding trailing blanks, use the following syntax:

length(var_name)

For example, to calculate the length of a character variable named “name”, we would use:

length(name)

Converting Numeric Variables to Character Variables

To find the length of a numeric variable in SAS, you can use the Length SAS function after converting the value to a character variable using the PUT function. Here are the steps:

1. Convert the numeric value into a character value with the PUT function.
2. Remove any unwanted characters, such as periods or dollar signs.
3. Calculate the length with the Length SAS function.

For example, to calculate the length of a numeric variable “ID_num”, we could use the following code:

length(put(ID_num,8.))

Changing the Length of a Character Variable

The length of a character variable in SAS can be changed using the Length statement. The syntax of the Length statement consists of three parts:

1. The keyword “length”.
2. The name of the variable you want to change.
3. A dollar sign followed by the desired length.

For example, to change the length of a character variable named “address” to 20 characters, we could use the following code:

length address $20;

Determining the Length of Binary Data

The LengthM function is used to determine the amount of memory in bytes allocated for binary data in SAS. This is particularly useful when working with large datasets with binary values. Here is the syntax:

lengthm(var_name)

For example, to determine the memory allocated for binary data in a variable named “bin_string”, we would use:

lengthm(bin_string)

Overall, these are just a few examples of how the Length SAS function can be used in SAS applications, proving to be a valuable tool for character string manipulation, particularly when working with large datasets.

Frequently Asked Questions

What is the difference between Length and Lengthm in SAS?

The Length SAS Function determines the string length of a character value while excluding the trailing blanks. In contrast, the Lengthm SAS Function determines the memory allocated for a character string in bytes.

How to use Length SAS Function in a DATA Step?

To use the Length SAS Function in a DATA Step, convert the numeric variable into a character variable using the PUT function. Remove unwanted characters and calculate the length using the Length SAS Function.

Can the Length SAS Function be used for numeric variables?

The Length SAS Function cannot be applied to numeric variables. It calculates the length of a character value and not the number of digits in a numeric variable.

References

List of trusted references related to the topic:

• SAS Documentation: Length Statement
• SAS Global Forum Proceedings 2017: Length Function Coding Techniques for SAS – A Tutorial

These references provide valuable information on how to use the SAS LENGTH function to compute the length of a string or character value, as well as examples and use cases which can help in learning the function better. The SAS documentation provides a comprehensive guide on the syntax and functionality of the LENGTH function, including relevant code examples. Meanwhile, the SAS Global Forum Proceedings discuss how to apply the Length function in real-world scenarios and provide insights into the best coding techniques for effectively utilizing the LENGTH function. These references can be a helpful guide for anyone looking to improve their skills in using the LENGTH function for SAS.