Regular Expressions 101

\d*a Unicode decimal digit, repeated any number of times

day-the literal text day- (case sensitive)

Group 1(.*?)

.*?any Unicode character (except for line terminators), repeated any number of times

--the literal text --

.*any Unicode character (except for line terminators), repeated any number of times

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.

Search reference

Regular Expression

\d*day-(.*?)--.*

New

2day-2023-1-5--20-0.csv
1day-2023-2-5--20-0.csv
3day-2021-1-5--20-0.csv