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This script compares two approaches to clean data where the value '9' represents a missing value. It first creates a test dataset. Then, it shows a manual and repetitive approach with multiple conditional statements, followed by a professional and concise approach using a SAS^© ARRAY and a DO loop to dynamically process all numeric variables.

Data Analysis

Type : CREATION_INTERNE

Data is generated directly within the script via the DATALINES statement.

1 Code Block

DATA STEP Data

Explanation :
Creation of the 'health_study' table with raw data included in the code.

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1	DATA health_study;
2	INPUT id expc listen good take hlprob share livaln livchld slpsick nerves exclude count tellfl
3	supress nocare satlife vigact liftgroc stairs bend;
4	DATALINES;
5	10001 9 0 1 1 1 0 0 9 0 0 0 1 1 1 0 1 1 9 1 9
6	10003 1 1 0 0 0 0 1 0 1 0 1 0 1 1 1 0 0 0 9 1
7	10004 0 0 1 0 0 1 1 0 9 1 0 0 1 0 0 1 9 1 1 1
8	10005 0 9 9 9 9 9 9 1 0 9 9 9 9 9 9 9 1 0 0 0
9	;
10	RUN;

2 Code Block

DATA STEP

Explanation :
Manual method: Using individual IF conditions for each variable to convert the value 9 to a missing value (.).

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1	DATA health_study2;
2	SET health_study;
3	IF expc = 9 THEN expc = .;
4	IF listen = 9 THEN listen = .;
5	IF good = 9 THEN good = .;
6	IF take = 9 THEN take = .;
7	IF hlprob = 9 THEN hlprob = .;
8	IF share = 9 THEN share = .;
9	IF livaln = 9 THEN livaln = .;
10	IF livchld = 9 THEN livchld = .;
11	IF slpsick = 9 THEN slpsick = .;
12	IF nerves = 9 THEN nerves = .;
13	IF exclude = 9 THEN exclude = .;
14	IF count = 9 THEN count = .;
15	IF tellfl = 9 THEN tellfl = .;
16	IF supress = 9 THEN supress = .;
17	IF nocare = 9 THEN nocare = .;
18	IF satlife = 9 THEN satlife = .;
19	IF vigact = 9 THEN vigact = .;
20	IF liftgroc = 9 THEN liftgroc = .;
21	IF stairs = 9 THEN stairs = .;
22	IF bend = 9 THEN bend = .;
23	RUN;

3 Code Block

DATA STEP

Explanation :
Optimized method: Using an ARRAY grouping all numeric variables (_numeric_) and an iterative loop to automatically apply the transformation to all columns.

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1	DATA health_study3;
2	SET health_study;
3	array variable {*} _numeric_;
4	DO i = 1 to dim(variable);
5	IF variable{i} = 9 THEN variable{i} = .;
6	END;
7	RUN;

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