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This script illustrates a common problem: modifying the length of a variable often changes its position in the table (it ends up at the end). The proposed solution uses metadata (SASHELP.VCOLUMN) to capture the initial order of variables, then uses the RETAIN statement in a DATA step combined with a LENGTH statement to apply the format change while forcing the column order defined by the macro variable.

Data Analysis

Type : SASHELP

Uses the example table 'sashelp.cars' as data source and 'sashelp.vcolumn' for structure metadata.

1 Code Block

DATA STEP Data

Explanation :
Creation of a 'cars' working table (in the WORK library) from a subset of columns from 'sashelp.cars'.

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1
2	DATA cars;
3	SET sashelp.cars (keep=Make Model Type Origin Drivetrain);
4	RUN;
5

2 Code Block

PROC SQL

Explanation :
Extraction of the list of variable names from the 'cars' table from the data dictionary (VCOLUMN), stored in the macro-variable ':varlist' to preserve the current order.

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1	PROC SQL noprint;
2	select name into :varlist separated BY ' '
3	from sashelp.vcolumn
4	where upcase(LIBNAME) eq 'WORK' and upcase(memname) eq 'CARS';
5	QUIT;

3 Code Block

DATA STEP Data

Explanation :
Reconstruction of the 'cars' table. The RETAIN statement (using the previously retrieved variable list) forces the column order. The LENGTH statement modifies the size of the 'Type' variable from 8 to 10 characters.

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1	DATA cars;
2	retain &varlist;
3	LENGTH Type $10;
4	SET cars;
5	RUN;

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