python - Find starting and ending indices of sublist in list

Question

I have a list:

greeting = ['hello','my','name','is','bob','how','are','you']

I want to define a function that will find the first and last index of a sublist in this list. Thus:

find_sub_list(['my','name','is'], greeting)

should return:

1, 3

Suggestions?

Answer 1

If you want multiple matches, this works:

greeting = ['hello','my','name','is','bob','how','are','you','my','name','is']

def find_sub_list(sl,l):
    results=[]
    sll=len(sl)
    for ind in (i for i,e in enumerate(l) if e==sl[0]):
        if l[ind:ind+sll]==sl:
            results.append((ind,ind+sll-1))

    return results

print find_sub_list(['my','name','is'], greeting) 
# [(1, 3), (8, 10)]

Or if you just want the first match:

greeting = ['hello','my','name','is','bob','how','are','you','my','name','is']

def find_sub_list(sl,l):
    sll=len(sl)
    for ind in (i for i,e in enumerate(l) if e==sl[0]):
        if l[ind:ind+sll]==sl:
            return ind,ind+sll-1

print find_sub_list(['my','name','is'], greeting)    
# (1, 3)