Regex returning empty string

Question

I am working on a regex problem from coursera and it has provided a data file of names followed by ": grade". We have to find and return the names of all the students who have a B. What I did was use this regex code

Bstudents = re.findall("(/w )*: B", grades)   #grades is the name of the variable with the names+grades.

There are supposed to be 16 students who have the grade B, but Instead of their names I am getting 16 blank strings.

here is the list:

Ronald Mayr: A
Bell Kassulke: B
Jacqueline Rupp: A 
Alexander Zeller: C
Valentina Denk: C 
Simon Loidl: B 
Elias Jovanovic: B 
Stefanie Weninger: A 
Fabian Peer: C 
Hakim Botros: B
Emilie Lorentsen: B
Herman Karlsen: C
Nathalie Delacruz: C
Casey Hartman: C
Lily Walker : A
Gerard Wang: C
Tony Mcdowell: C
Jake Wood: B
Fatemeh Akhtar: B
Kim Weston: B
Nicholas Beatty: A
Kirsten Williams: C
Vaishali Surana: C
Coby Mccormack: C
Yasmin Dar: B
Romy Donnelly: A
Viswamitra Upandhye: B
Kendrick Hilpert: A
Killian Kaufman: B
Elwood Page: B
Mukti Patel: A
Emily Lesch: C
Elodie Booker: B
Jedd Kim: A
Annabel Davies: A
Adnan Chen: B
Jonathan Berg: C
Hank Spinka: B
Agnes Schneider: C
Kimberly Green: A
Lola-Rose Coates: C
Rose Christiansen: C
Shirley Hintz: C
Hannah Bayer: B

Use a tool like regex101.com - it allows you to [specify Python as your regEx engine and] tweak your pattern and see in real time what does/doesn't match. — Adam Smooch
– Adam Smooch, Commented Aug 5, 2021 at 13:48

Alireza · Accepted Answer · 2021-08-05 14:04:35Z

2

You can use positive lookahead: [\w ]+(?=: B)

See Demo

edited Aug 5, 2021 at 14:04

answered Aug 5, 2021 at 13:48

Alireza

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3 Comments

Haamed Rahman Over a year ago

was the problem that I didn't use () to identify ": B" or was it because I used "*" instead of "+"?

Alireza Over a year ago

Almost none of them, see the link.

Alireza Over a year ago

We know every grade have name of a student before it so we can use + that means one or more character instead of * that means zero or more

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