Python string.join ( list ) last entry with “and”

Question

What is an elegant way to join a list of sentence parts so that the result is \"a, b, and c\" where the list is [ \'a\', \'b\', \'c\' ]? Specifying

Answer 1

Assuming len(words)>2, you can join the first n-1 words using ', ', and add the last word using standard string formatting:

def join_words(words):
    if len(words) > 2:
        return '%s, and %s' % ( ', '.join(words[:-1]), words[-1] )
    else:
        return ' and '.join(words)

Answer 2

L = ['a','b','c']

if len(L)>2:
    print ', '.join(L[:-1]) + ", and " + str(L[-1])
elif len(L)==2:
    print ' and '.join(L)
elif len(L)==1:
    print L[0]

Works for lengths 0, 1, 2, and 3+.

The reason I included the length 2 case is to avoid commas: a and b.

If the list is length 1, then it just outputs a.

If the list is empty, nothing is outputted.

Answer 3

l = ['a','b','c']
if len(l) > 1:
    print ",".join(k[:-1]) +  " and " + k[-1]
else:print l[0]

exapmles:

l = ['a','b','c']
a,b and c

l = ['a','b']
a and b

l=['a']
a

Answer 4

"{} and {}".format(",".join(l[:-1]),l[-1]) if len(l) > 1 else l[0]


In [25]: l =[ 'a']

In [26]: "{} and {}".format(",".join(l[:-1]),l[-1]) if len(l) > 1 else l[0]
Out[26]: 'a'

In [27]: l =[ 'a','b']

In [28]: "{} and {}".format(",".join(l[:-1]),l[-1]) if len(l) > 1 else l[0]
Out[28]: 'a and b'

In [29]: l =[ 'a','b','c']

In [30]: "{} and {}".format(",".join(l[:-1]),l[-1]) if len(l) > 1 else l[0]
Out[30]: 'a,b and c'