how should I find names with a shared characters in a list names in python?

Question

I have a list of names, let's say like ['R_1', 'ER_1',ER_2''R_2','R_3', 'ER_1',ER_2', 'C1', 'R_5',...]. Then I want to find those which has 'R' in common, or 'ER'. Which command should I use? I would like to find these later in pandas.

Answer 1

l = ['R_1', 'ER_1', 'ER_2', 'R_2', 'R_3', 'ER_1', 'ER_2', 'C1', 'R_5']

# create a list with your keys (i.e. the string before the "_") 
keys = list(set([el.split("_")[0] for el in l]))

# put them in a dictionary of the form {key1: [key1_x, key1_y], key2: [key2_z, key2_x], ...}
groups = {k: [el for el in l if el.split("_")[0] == k] for k in keys}