Regular expressions are one of those things on the software development world that give me nausea when I come across them. Reading something like this in code just makes me shiver:
^(ht|f)tp(s?)\:\/\/[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*(:(0-9)*)*(\/?)([a-zA-Z0-9\-\.\?\,\’\/\\\+&%\$#_]*)?$
It seems to me like cartoon characters swearing: &$^%#&%@&$#**^&$. 
I just happened to run accross a little article (found at that taught something I didn’t know about regular expression: one can put comments on them!
So, instead of having some cryptic code like this one:
Regex regex = new Regex(@"^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}\s$);
One could make the world a favor and rewrite that code like so:
Regex regex = new Regex(@"
^ # anchor at the start
(?=.*\d) # must contain at least one numeric character
(?=.*[a-z]) # must contain one lowercase character
(?=.*[A-Z]) # must contain one uppercase character
{8,10} # From 8 to 10 characters in length
\s # allows a space
$ # anchor at the end",
RegexOptions.IgnorePatternWhitespace);
^ # anchor at the start
(?=.*\d) # must contain at least one numeric character
(?=.*[a-z]) # must contain one lowercase character
(?=.*[A-Z]) # must contain one uppercase character
{8,10} # From 8 to 10 characters in length
\s # allows a space
$ # anchor at the end",
RegexOptions.IgnorePatternWhitespace);
That way, even my little brain can understand a freakin’ regular expression.
Claudio Lassala's Blog 
#1 by Bob Barker on May 14, 2020 - 11:12 am
another idea is that regexes are just text so you can save them as variables and use them in that way.
it’s also possible to use them with string interpolation“`
import re
text_to_search = ”’
321-555-4321
123.555.1234
123*555*1234
800-555-1234
900-555-1234
”’
sentence = ‘Start a sentence and then bring it to an end’
three_digits = r’\d\d\d’
four_digits = r’\d\d\d\d’
dot_or_dash = r'(\.|-)’
pattern = re.compile(three_digits + dot_or_dash + three_digits + dot_or_dash + four_digits)
# string interpolation
matches = pattern.finditer(text_to_search)
print(‘starting…’)
for match in matches:
print(match)
“`
#2 by Bob Barker on May 14, 2020 - 11:14 am
edit: I hit something and it submitted my post when I wasn’t ready it was supposed to say:
“`
# string interpolation
pattern = re.compile(rf'{three_digits}(\.|-){three_digits}(\.|-){four_digits}’)
matches = pattern.finditer(text_to_search)
“`
#3 by claudiolassala on May 18, 2020 - 2:46 pm
Woah, that’s pretty cool. I didn’t know it could be done that way. Thanks for sharing, Bob!
#4 by claudiolassala on May 18, 2020 - 2:48 pm
Come to think of it, I do remember using string interpolation but couldn’t remember about the “compile” method. It’s been a while. Anyway, anything to make those expressions more readable. 🙂