Why do certain functions such as REVERSE and TRANSLATE add trailing blanks to match string length?

[sass_numero_uno]

[SAS 7.1] Why do certain functions such as REVERSE and TRANSLATE add trailing blanks to match string length to the longest string in that field?

E.g.

1

12

123

1234

12345

When reversed, becomes

1____

21___

321__

4321_

54321

Where underscores represent blanks.

[Reeza · Accepted solution]

SAS pads strings with blanks to take up the assigned length. 

This only becomes apparent when you're trying to do something and white space is a factor, such as string functions.

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@sass_numero_uno wrote:

[SAS 7.1] Why do certain functions such as REVERSE and TRANSLATE add trailing blanks to match string length to the longest string in that field?

E.g.

1

12

123

1234

12345

When reversed, becomes

1____

21___

321__

4321_

54321

Where underscores represent blanks.

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[sass_numero_uno]

Do you know why this happens?

[Tom]

They don't ADD any spaces.  They just don't remove them.

Your description of the how REVERSE works is wrong.  If you reverse a string of length 5 then the original trailing spaces will now be at  the beginning. 

Perhaps you started with values that had LEADING spaces?  Perhaps as the output of the PUT() function or some other numeric to character conversion? 

Note that the normal PUT statement that either does not use a format or uses the generic character format $ will remove leading/trailing  spaces while writing.  You can use a different format to see the spaces. Like $CHAR or $QUOTE format.