Data standardization and temperature conversions with PROC IML

Difficulty Level

Beginner

Published on : 26/05/2023

The script begins by standardizing the numerical variables of the SASHELP.CLASS dataset using the median as the center and the MAD (Median Absolute Deviation) as a robust scale. Then, it performs temperature conversions from Celsius to Fahrenheit and Kelvin, illustrating basic matrix operations in IML. Finally, a simple arithmetic calculation example is presented.

Data Analysis

Type : MIXTE

The script uses the SASHELP.CLASS dataset for standardization. Temperature data and variables 'x', 'y' are created directly within the IML script.

1 Code Block

PROC IML

Explanation :
This block starts by defining a `SPI` library pointing to `SASUSER`. It then initializes a `PROC IML` session to read the numerical variables from the `SASHELP.CLASS` dataset. It calculates the median (`c`) and MAD (`s`) of each variable, then standardizes the data (`stdX`) and displays the calculated statistics.

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1	LIBNAME SPI (SASUSER); /* location of data sets */
2
3	PROC IML;
4	/* standardize data by using robust estimates of center and scale */
5	use Sashelp.Class; /* open data set for reading */
6	read all var _NUM_ into x[colname=VarNames]; /* read variables */
7	close Sashelp.Class; /* close data set */
8
9	/* estimate centers and scales of each variable */
10	c = median(x); /* centers = medians of each column */
11	s = mad(x); /* scales = MAD of each column */
12	stdX = (x - c) / s; /* standardize the data */
13
14	PRINT c[colname=VarNames]; /* print statistics for each column */
15	PRINT s[colname=VarNames];

2 Code Block

PROC IML Data

Explanation :
This block creates a `Celsius` vector with several values. It then converts these temperatures to Fahrenheit and Kelvin degrees using matrix operations and displays the results.

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1	/* convert temperatures from Celsius to Fahrenheit scale */
2	Celsius = {-40, 0, 20, 37, 100}; /* some interesting temperatures */
3	Fahrenheit = 9/5 * Celsius + 32; /* convert to Fahrenheit scale */
4	PRINT Celsius Fahrenheit;
5
6	Kelvin = Celsius + 273.15; /* convert to Kelvin scale */
7	PRINT Kelvin;

3 Code Block

PROC IML Data

Explanation :
This block illustrates a simple arithmetic calculation in IML: assigning values to `x` and `y`, adding them to obtain `z`, then displaying the result. The `PROC IML` session ends with the `quit` statement.

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1	/* Present a simple example program with comments. */
2	/* The PROC IML statement is not required in SAS/IML Studio programs. */
3	x = 3; /* 1 / / NUMBERS indicate steps that */
4	y = 2; /* are described in a list */
5	z = x + y; /* 2 / / AFTER the program. */
6
7	PRINT z; /* display result / / Other statements are briefly */
8	/* described WITHIN the program. */
9
10	QUIT;

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Difficulty Level

Published on : 26/05/2023

Data Analysis

1 Code Block

2 Code Block

3 Code Block

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