This feature relies on the SAS PRXPARSE function, which uses metacharacters in constructing a Perl regular expression. This expression is applied to the whole filename including the extension. A few of the most common uses are given below.
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Single alphanumeric string. The filter “dat” (without the quotation marks) would show all .dat files but also .sas7bdat files or any filename that contains “dat”.
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Single file extension. To display .dat files only, you can specify “\.dat” (without the quotation marks). Note the backslash (\) preceding the period. The period normally is interpreted as a metacharacter, which matches any single character, so the backlash overrides the normal use of the period metacharacter and instead forces interpretation of the literal period.
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Multiple file extensions. To display files with .txt, .dat, or .abc extensions only, specify “\.txt|\.dat|\.abc” (without the quotation marks). Note the use of the vertical bar (|) as an OR operator.
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Specific file base and extension. To display any .txt file starting with the word “test” in its base (such as test001.txt, test002.txt, testnnn.txt), specify “^test*\.txt” (without the quotation marks). Note the use of the caret (^) to indicate that matches should be made at the beginning of the filename (this avoids displaying a file such as firsttest001.txt).
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The examples above only touch the surface of what is possible using the powerful regular expression syntax. Refer to the SAS Online Documentation for the PRXPARSE function for additional details.
