Regular Expressions 101

^start of line

Non-Capturing Group(?:(?:pdf|csv|xlsx?)/?\b)+

+repeats the group contents below at least once:

Non-Capturing Group(?:pdf|csv|xlsx?)

1st Alternativepdf

pdfthe literal text pdf (case sensitive)

2nd Alternativecsv

csvthe literal text csv (case sensitive)

3rd Alternativexlsx?

xlsthe literal text xls (case sensitive)

x?optionally matches the literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

/?optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

\ba Unicode word boundary

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

27 tokens

Regular Expression

^(?:(?:pdf|csv|xlsx?)/?\b)+$

New

For example, correct flow:

pdf/csv/xlsx
pdf
pdf/csv
csv/xlsx
xlsx
pdf/xlsx

Incorrect:

test
incorrect
doc