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

If string 'IP' only exists at the head of some elements of a, join the list and then split it:

In [99]: ['IP'+i for i in ''.join(a).split('IP')[1:]]
Out[99]: 
['IP 123 84applemercury',
 'IP 543 65killerparsergoat',
 'IP 549 54 pineappledjangopython']

If a is like

a = ['IP 123 84', 'apple', 'mercury', 'IP 543 65', 'killer', 'parserIP', 'goat',
     'IP 549 54 pineapple', 'django', 'python']                    ^^^^

the former solution won't work, you may insert some special sequence (which should never appear in a) to a, and then join & split it:

In [11]: for i, v in enumerate(a):
    ...:     if v.startswith('IP'):
    ...:         a[i]='$$$'+v
    ...: ''.join(a).split('$$$')[1:]
Out[11]: 
['IP 123 84applemercury',
 'IP 543 65killerparsergoat',
 'IP 549 54 pineappledjangopython']