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Frequent Visitor

Filename format check

What is the best way to check of the format of a filename complies to a standard?

Our standard looks like this: BC1234-BAM-XX-XX-BQ-CN-0085.docx

Project is alphanumerical  6 characters
Originator is alphanumerical 3 characters
Level, Location, Type and role are alphanumerical 2 characters
Number has a minimum length of 4 characters (so below 1000 leading zero's are added)

I was thinking to use find to check if the - appears 6 times and  substring to check if they are on the right position
substring(variables('filename'), 6,1 ) should be a - sign.

I'm not sure how to put this together.



Super User
Super User

Hi @rolanddaane 


Flow doesn't yet support regular expressions, yet you can build something using Typescript/Office Scripts How to use Regex in Power Automate (  More recently, there is the option to create a C# Custom Connector, which might also suite your needs/requirements.


If neither apply, you could use the expression split(string,'-').  It will return an array of objects split on the -.  You can then check each of the objects as you require?


If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

P.S. take a look at my new blog here and like & subscribe to my YouTube Channel thanks 😉


Frequent Visitor

I subscribed and already liked your intro video.
Are you based in the UK?

Hi @rolanddaane 


I am indeed - North East Scotland!



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