I am trying to match string with mypattern, somehow I do not get correct result. Can you please point where am I wrong? 
import re
mypattern = '_U_[R|S]_data.csv'
string =  'X003_U_R_data.csv'
re.match(mypattern, string)
I am trying to match string with mypattern, somehow I do not get correct result. Can you please point where am I wrong? 
import re
mypattern = '_U_[R|S]_data.csv'
string =  'X003_U_R_data.csv'
re.match(mypattern, string)
 
    
    I like to compile the regex statement first. Then I do whatever kind of matching/searching I would like.
mypattern = re.compile(ur'_U_[R|S]_data.csv')
Then
re.search(mypattern, string)
Here's a great website for regex creation- https://regex101.com/#python
