how to check if file path finish on .csv

[danlopek14q]

Hello guys

I have a simple problem finding how can I check if the file path entered by the user does end in for example with .csv
The user enters the file path for a data file (e.g. 'file/myfolder.csv').
If the file path entered by the user does not end in 'csv' then error should be displayed otherwise it should return the path