Merge list items based on condition within the list

Question

I have a list of items : eg:

a = [\'IP 123 84\', \'apple\', \'mercury\', \'IP 543 65\', \'killer\', \'parser\', \'goat\',
     \'IP 549 54 pineapple\', \'dja         


        

Answer 1

Kind of a fun way to do it:

import itertools

def predicate_grouper(li, predicate='IP'):
    indices = [i for i,x in enumerate(li) if x.startswith(predicate)]
    slices = [slice(*x) for x in itertools.zip_longest(indices,indices[1:])]
    for sli in slices:
        yield ' '.join(li[sli])

demo:

list(predicate_grouper(a))
Out[61]: 
['IP 123 84 apple mercury',
 'IP 543 65 killer parser goat',
 'IP 549 54 pineapple django python']