Macro addvar - Text variable splitting

Difficulty Level

Beginner

Published on : 22/10/2021

The `addvar` macro analyzes a given variable in an input table. If the content length exceeds `maxlen` (default 200), it uses an external macro `%gmModifySplit` to prepare the splitting, then distributes the text into several new indexed variables using a defined separator. If the length is below the limit, the variable is simply formatted and copied. Note that the macro modifies the input table (`&in_data`) if splitting is enabled.

Data Analysis

Type : EXTERNE

Data is defined by the `in_data` macro parameter. The script expects to receive an existing table.

1 Code Block

PROC SQL

Explanation :
Calculates the maximum length of the text variable in the input table to determine if splitting is required.

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1	PROC SQL noprint;
2	select distinct max(LENGTH(&in_var)) into :lngth
3	from &in_data;
4	QUIT;

2 Code Block

DATA STEP Data

Explanation :
Executed if the length exceeds the limit: Preparation of the input table by renaming the variable and calling the external macro `%gmModifySplit`.

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1	DATA &in_data;
2	SET &in_data(rename=&in_var=_&in_var._);
3	%gmModifySplit(var=_&in_var._, width=&maxlen);
4	RUN;

3 Code Block

PROC SQL

Explanation :
Determines the number of additional variables needed by counting separator occurrences.

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1	PROC SQL noprint;
2	select cats(max(count(_&in_var._, "&split"))) into :varn
3	from &in_data;
4	QUIT;

4 Code Block

DATA STEP Data

Explanation :
Creation of the final output table. The text is split into an array of variables (`vlst`) using the `scan` function.

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1	DATA &out_data;
2	SET &in_data;
3	array vlst{*} $200 &out_pre. &out_pre.1 - &out_pre.&varn;
4	DO i=1 to %eval(&varn+1);
5	vlst(i)=scan(_&in_var._, i, "&split");
6	END;
7	drop _&in_var._ i;
8	RUN;

5 Code Block

DATA STEP Data

Explanation :
Alternative (ELSE): If no splitting is required, the output table is created with the variable simply adjusted to the standard length.

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1	DATA &out_data;
2	SET &in_data(rename=&in_var=_&in_var._);
3	LENGTH &out_pre $200;
4	&out_pre=_&in_var._;
5	RUN;

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Difficulty Level

Published on : 22/10/2021

Data Analysis

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