import re
 
data = ['abc123','abc*123&','Abc123','ABC@*&123','123*Abc', '123_abc', '123 abc']
alphanumeric_underscore = [re.sub('\W', '', item) for item in data]  # replace non-alphas and non-digits; filter [A-Za-z0-9_]
print('alphanumeric_underscore', alphanumeric_underscore)
alphanumeric = [re.sub('[\W_]', '', item) for item in data]  # replace also the underscore; filter [A-Za-z0-9]
print('alphanumeric', alphanumeric)
numeric = [re.search(r"\d+", item).group(0) for item in data]  # filter only digits
print('numeric', numeric)
alpha = [re.search(r"[A-Za-z]+", item).group(0) for item in data]  # filter only alphas
print('alpha', alpha)

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