How to find files that the filenames start with 3 digits?

[Anonymous]

I have many files in a folder and the filenames fall into different patterns:

123 store_location1.xlsm

234 store_location2.xlsm

235 store_location3.xlsm

....

1 - Grocery.xlsm

2 - Dairy.xlsm

...

Division 1 - Grocery.xlsm

Division 2 - Grocery.xlsm

...

How can I get only these files that the names start with 3 digits?

Please help!

[Jesperrekuh · Accepted solution]

tFileList use regex expression to filter...
"^[0-9]{3}.+xlsm$"

Take a closer look at (java) regex in general, this will open up pandoras box regarding string matching searching and even replacing... pretty awesome.
http://www.regexplanet.com/advanced/java/index.html

[Anonymous]

Thank you Dijke very much for your quick response!

If I want to filter the ones that filenames start with 3 digits, and the extension could either be .xlsm or .xls, 

should the modified regex expression to be:

"^[0-9]{3}.+xls$"
?

Could you please give a quick explanation about how this expression works?

Thanks!

TM

[Anonymous]

add a question mark ? after the m to optionally match the m

^[0-9]{3}.+xlsm?$

^ match start of line
[0-9]{3} match 3 numbers that range from 0-9
.+ match any character one or more times
xlsm? match the letters "xls" and optionally "m"
$ match end of line

[Anonymous]

Can anyone recommend a site for people like me to learn Regex Expression step by step?

[Jesperrekuh]

here you go :
http://www.vogella.com/tutorials/JavaRegularExpressions/article.html
This link a little more related to java coding:
https://regexone.com/references/java

This site is to test and experiment/validate your expressions: http://www.regexplanet.com/advanced/java/index.html