Xtykutl

I have a list with different email formatting, which I want to unify all in one.
There are 2 types of email:

name.surname@dom

name.surname.extern@dom

My program allows the user to input emails, and to not have to enter "@dom" all the time (it's always the same one), what I've done is allowing the user to write name.surname or name.surname.e and then the script replaces those usernames with @dom or .extern@dom
The problem rises when I have all the mails in different formats stores in a list, and I want them to be filled to standards, so that if I have

["john.doe@dom", "john2.doe", "john3.doe.e","john4.doe.extern@dom"]

it all ends up looking like this

["john.doe@dom", "john2.doe@dom", "john3.doe.extern@dom","john4.doe.extern@dom"]

I have tried with list comprehensions, but all I got was three concatenations:

["%s.xtern@dom" % x for x in mails if x[-2:] == ".e"] +

["%s@dom" %x for x in mails if "@dom not in mails" and x[-2:] != ".e"] + 

[x for x in mails if "@dom" in x]

I'm sure there's a better way that does not require me to do 3 list comprehensions and that does not require me to do

for i,v in enumerate(mails):

    if "@dom" not in v:

        mails[i] = "%s@dom" % v

    etc.

You can use a string's endswith() method to determine what you need to do with the input:

mails = ["john.doe@dom", "john2.doe", "john3.doe.e","john4.doe.extern@dom"]



final_mails = 



for mail in mails:

    if mail.endswith("@dom"):

        # Use as-is if it ends with @dom.

        final_mails.append(mail)

    elif mail.endswith(".e"):

        # Replace to extern@dom if it ends with .e

        final_mails.append(mail.replace(".e", ".extern@dom"))

    else:

        # Add @dom on all other cases

        final_mails.append("{}@dom".format(mail))



print final_mails



# Result: ['john.doe@dom', 'john2.doe@dom', 'john3.doe.extern@dom', 'john4.doe.extern@dom']

It might need more thorough checks to not accept things like @dom right in the middle of the name and whatnot. Hope that helps you out though!

Edit:
Just for fun, if you insist on a list comprehension:

mails = ["john.doe@dom", "john2.doe", "john3.doe.e","john4.doe.extern@dom"]



final_mails = ["{}@dom".format((mail.replace(".e", ".extern@dom") 

               if mail.endswith(".e") else mail).rstrip("@dom")) 

               for mail in mails]



print final_mails



# Result: ['john.doe@dom', 'john2.doe@dom', 'john3.doe.extern@dom', 'john4.doe.extern@dom']

Personally I find list comprehensions are best when they are short and readable, so I would stick with the first option.

Option without listcomprehensions:

maillist = ["john.doe@dom", "john2.doe",    "john3.doe.e","john4.doe.extern@dom"]



for i in range(len(maillist)): 

    if "@" not in maillist[i]:

        if maillist[i][-2:]== ".e": 

            maillist[i] += ("xtern@dom") 

        else: 

            maillist[i] +=  "@dom"

@Green Cell was faster than me and his answer seems to be correct. Here is a list comprehension that does the same thing :

mails = ["john.doe@dom", "john2.doe", "john3.doe.e","john4.doe.extern@dom"]



print mails



mails = [mail if mail.endswith("@dom") else mail.replace(".e", ".extern@dom") if mail.endswith(".e") else "{}@dom".format(mail) for mail in mails]



print mails

Which outputs :

['john.doe@dom', 'john2.doe', 'john3.doe.e', 'john4.doe.extern@dom']

['john.doe@dom', 'john2.doe@dom', 'john3.doe.extern@dom', 'john4.doe.extern@dom']

Hope this helps.

if you want a one-liner, combine list comprehension with multiple if/else statements:

first_list = ["john.doe@dom", "john2.doe", "john3.doe.e","john4.doe.extern@dom"]



second_list = [email + 'xtern@dom' if email.endswith(".e") else 

               email if email.endswith("@dom") else "{}@dom".format(email) 

                   for email in first_list]



print second_list

Gives:

['john.doe@dom', 'john2.doe@dom', 'john3.doe.extern@dom', 'john4.doe.extern@dom']

I came with a different solution in the end: Declaring a help function.

def mailfy(mail):

   if mail.endswith(".c"):

     return mail[:-2] + "@dom"

   ...



mails = [mailfy(x) for x in mails]