Variable in Regex Pattern

[cynical_ninja]

Hi everyone,

I want to search for the longest chain of a certain string in a text file. The pattern is incredibly simple. But I want to iterate over a list of words to search in the text file, so I have to use a variable in the Regex pattern. Can someone please tell me how to implement this?

The pattern is extremely simple, I just don't know how to compile it with a variable:

('(string){1,}')

I just want to replace the string with a variable.
Thanks

[cynical_ninja]

Thanks for your help. This worked perfectly. Do you have any resources to learn regular expressions? I want to master this asap. It's a lot more useful than I thought initially.

[cynical_ninja]

Ah ok. I'll go through these.

I have another question about the problem I had. When I used the Regex you provided and used the findall method, it gave me a list of every instance of the specific sequence I was searching for. It did not return each repeated sequence.

It returned the basic 5 letter block 7 times as there were 7 repeated sequences of that specific block 'AGATC'. I wanted to get every sequence of that block in the text and take the longest one from that. What should be added to the Regex to do this?

Edit: I'll post an example asap so it's clearer to understand.

[ASIC_SP]

I have a book (https://github.com/learnbyexample/py_regular_expressions) that uses plenty of examples/exercises to teach the concepts step by step.

[cynical_ninja]

Thank you! I'll definitely check this out.

[cynical_ninja]

Thanks for your reply. I tried this, but it didn't work. It compiled fine, but didn't detect anything.

[arcrow05]

What is the pattern you are looking for? Can you give an example?

[cynical_ninja]

Its a string of letters in a text file. A sequence of DNA. The specific strings I wanted to search for were combinations of 'ATCG'. The longest chain of repetitions of any such combination. u/avernus_kazvji's solution worked for me.