What would be the most efficient way to generate groups of similar items in a large list in the given order? ex: ['a','b','b','c','c','c','b','c','c'] --> [['a'],['b','b'],['c','c','c'],['b'],['c','c']]
My current solution is to use a simple iterator and work my way through the list. This works fine. But i would love to know of better alternatives. Especially when dealing with very long lists of 1 million entries or more.
def grouper(items):
grp = []
for i in items:
if grp and i != grp[-1]:
if grp:
yield grp
grp = [i]
else:
grp.append(i)
if grp:
yield grp
new = []
for x in grouper(['a','b','b','c','c','c','b','c','c']):
# Do something useful with this group
for x in grouper(data):
print '#>>>%s'%x
#>>>['a']
#>>>['b', 'b']
#>>>['c', 'c', 'c']
#>>>['b']
#>>>['c', 'c']
