In SAS, there are several different input methods that can be used to read data into a SAS program. The choice of input method depends on the format and structure of the data being read. Here are some of the most common input methods in SAS:
1. Data step input: This is the most basic method of input in SAS, and involves reading data directly from an external file using a data step. In a data step, the INPUT statement is used to define the variables to be read and their formats. For example:
data mydata;
infile ‘mydata.txt’;
input var1 var2;
run;
2. List input: List input is a simple method of input in SAS that is used when the data is arranged in columns, with each variable separated by a delimiter such as a comma or space. In a data step, the INPUT statement can be used to read the data directly into variables. For example:
data mydata;
input var1 var2 var3;
datalines;
1 2 3
4 5 6
7 8 9
;
run;
3. Formatted input: Formatted input is a more complex method of input in SAS that is used when the data has a more structured format, such as when using fixed-length fields. In a data step, the INPUT statement is used to define the variable formats, which can include both character and numeric values. For example:
data mydata;
infile ‘mydata.txt’;
input var1 $1–10 var2 12–15;
run;
4. External file input: External file input is used when the data to be read is stored in an external file, such as a CSV file, an Excel file, or a database. In SAS, external files can be read using specialized input methods such as the INFILE statement, the LIBNAME statement, or ODBC/OLE DB connectivity.
5. SQL input: SAS also provides the ability to read data directly from a SQL database using SQL queries. This is done using the PROC SQL statement, which allows users to create queries and join tables from within the SAS environment.
These are just a few of the different input methods available in SAS. The choice of input method depends on the structure and format of the data being read, as well as the user’s specific needs and preferences.
column input method
Column input is a type of data input method in SAS that is used when data is arranged in columns with fixed lengths. This method is typically used when data is in a specific fixed format and the position of each data field is known. In column input, data is read by specifying the start and end positions of each data field in the input record.
Here is an example of how to use column input in SAS:
data mydata;
infile ‘datafile.txt’;
input var1 $1–10 var2 11–20 var3 21–30;
run;
In this example, the INFILE statement specifies the external file to be read, and the INPUT statement defines the variables to be created and their respective column positions in the input record. Specifically, the first variable “var1” is a character variable that starts at column 1 and ends at column 10, the second variable “var2” is a numeric variable that starts at column 11 and ends at column 20, and the third variable “var3” is a character variable that starts at column 21 and ends at column 30.
When the data is read using this input method, SAS reads the data from left to right and assigns the values to the appropriate variables based on their positions in the input record.
Column input can be very useful when working with data that has a fixed and structured format, such as financial data or data from scientific experiments. By specifying the exact column positions for each variable, the data can be read and processed quickly and accurately in SAS.
Name input method:
The name input method is a type of data input method in SAS that is used when data is not arranged in fixed positions or columns, but is instead separated by a delimiter, such as a space or comma. In this method, data is read using variable names rather than column positions, and each variable is separated by the delimiter in the input record.
Here is an example of how to use the name input method in SAS:
data mydata;
infile ‘datafile.txt’ dlm=’,’;
input var1 $ var2 var3;
run;
In this example, the INFILE statement specifies the external file to be read, and the DLM= option specifies the delimiter used to separate the variables in the input record (in this case, a comma). The INPUT statement defines the variables to be created, and each variable is separated by the delimiter in the input record.
When the data is read using this input method, SAS reads the data from left to right and assigns the values to the appropriate variables based on their names. The first variable “var1” is a character variable that is delimited by a comma and read until the next comma or end of line, and the second and third variables “var2” and “var3” are numeric variables that are delimited by commas and read until the next comma or end of line.
The name input method is useful when working with data that is not in a fixed format, such as data from surveys or questionnaires. By specifying the delimiter used to separate the variables, SAS can read and process the data quickly and accurately, without the need for pre-formatting the data.
what are the format and informat methods?
In SAS, format and informat are two methods used for data input and output.
An informat is a SAS instruction that tells SAS how to read data. It is used to convert raw data into a SAS data set. Informat specifies the type of data (numeric or character), the width of the input data, and how the data is to be interpreted. Some commonly used informats include MMDDYY (for date values in the format of month, day, and year), DOLLAR (for numeric values in dollar format), and PERCENT (for numeric values in percentage format).
A format is a SAS instruction that tells SAS how to display data. It is used to convert SAS data into a human-readable format. Formats specify the type of data (numeric or character), the width of the output data, and how the data is to be displayed. Some commonly used formats include DATE (for date values), DOLLAR (for numeric values in dollar format), and PERCENT (for numeric values in percentage format).
Both informats and formats can be customized using user-defined formats and informats. User-defined formats and informats allow users to create their own formats and informats to suit their specific needs.
Here is an example of how to use an informat and a format in SAS:
data mydata;
infile ‘datafile.txt’;
input name $ age weight;
informat age best12.;
format weight dollar8.2;
datalines;
John 25 150
Jane 32 180
Tom 40 200
;
run;
In this example, the INFILE statement specifies the external file to be read, and the INPUT statement defines the variables to be created. The INFORMAT statement specifies that the variable “age” should be read using the BEST12. informat. The FORMAT statement specifies that the variable “weight” should be displayed using the DOLLAR8.2 format.
When the data is read and processed using these instructions, SAS reads the data using the specified informat and displays the data using the specified format, making it easy to work with and analyze data in SAS.
