python - Join author names with first ones separated by comma and last one by "and" -

i'm new python , have list of names separated \and, need join separating first ones comma , last 1 'and'. if there more 4 names return value should first name along phrase 'et al.'. if have

 authors = 'john bar \and tom foo \and sam foobar \and ron barfoo' 

i should 'john bar et al.'. whereas with

authors = 'john bar \and tom foo \and sam foobar' 

i should 'john bar, tom foo , sam foobar'.

it should work 1 author name, returning single name (and surname) itself.

i tried doing like

  names = authors.split('\and')   result = ', '.join(names[:-1]) + ' , '.join(names[-1]) 

but doesn't work. question how can use join , split first authors separated comma , last 'and' taking account if there more 4 authors first author name should returned along 'et al.'.

start splitting out names:

names = [name.strip() name in authors.split(r'\and')]  # assuming raw \ here, not escape code \a. 

then rejoin based on length:

if len(names) >= 4:     authors = '{} et al.'.format(names[0]) elif len(names) > 1:     authors = '{} , {}'.format(', '.join(names[:-1]), names[-1]) else:     authors = names[0] 

this works entries one author too; reassign name authors.

combined function:

def reformat_authors(authors):     names = [name.strip() name in authors.split(r'\and')]     if len(names) >= 4:         return '{} et al.'.format(names[0])     if len(names) > 1:         return '{} , {}'.format(', '.join(names[:-1]), names[-1])     return names[0] 

with demo:

>>> reformat_authors(r'john bar \and tom foo \and sam foobar \and ron barfoo') 'john bar et al.' >>> reformat_authors(r'john bar \and tom foo \and sam foobar') 'john bar, tom foo , sam foobar' >>> reformat_authors(r'john bar \and tom foo') 'john bar , tom foo' >>> reformat_authors(r'john bar') 'john bar'