Question

Consider a list o emails:

['[e-mail]','[e-mail]','[e-mail]',...]

I want to compare list items with each other. For example emails would be unique.
What is the way for compare items of list with each other in Python?

Answer 1

If you just want to test whether or not there were duplicates in the list, you can use:

if len(set(list_o_emails)) == len(list_o_emails):
    # all are different
else:
    # you had a duplicate
    raise forms.ValidationError # from your comment

since set will eliminate any duplicates for you and comparing the lengths will tell you whether or not any duplicates were removed.