You could just iterate over the indices of the range of the len of your list:

dataList = [{'a': 1}, {'b': 3}, {'c': 5}]
for index in range(len(dataList)):
    for key in dataList[index]:
        print(dataList[index][key])

or you could use a while loop with an index counter:

dataList = [{'a': 1}, {'b': 3}, {'c': 5}]
index = 0
while index < len(dataList):
    for key in dataList[index]:
        print(dataList[index][key])
    index += 1

you could even just iterate over the elements in the list directly:

dataList = [{'a': 1}, {'b': 3}, {'c': 5}]
for dic in dataList:
    for key in dic:
        print(dic[key])

It could be even without any lookups by just iterating over the values of the dictionaries:

dataList = [{'a': 1}, {'b': 3}, {'c': 5}]
for dic in dataList:
    for val in dic.values():
        print(val)

Or wrap the iterations inside a list-comprehension or a generator and unpack them later:

dataList = [{'a': 1}, {'b': 3}, {'c': 5}]
print(*[val for dic in dataList for val in dic.values()], sep='\n')

the possibilities are endless. It's a matter of choice what you prefer.

When you iterate over a list, you get the elements, not the indices. Consider

for car in cars:
  for x, y in car["coded"].items():
    print(x, y)

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You could use a generator to only grab ages.

# Get a dictionary 
myList = [{'age':x} for x in range(1,10)]

# Enumerate ages
for i, age in enumerate(d['age'] for d in myList): 
    print i,age

And, yeah, don't use semicolons.

While operator.itemgetter is a more efficient alternative to an equivalent lambda function, it does not beat normal dictionary lookup [], and using it for that purpose makes code harder to read.

Your code looks very complicated to me and I find it hard to follow, but the most likely bottleneck is the five-fold nested for loop.

In there, my first thought would be to consider if these lines...

            for pred in getter(val):
                for items in getter_2(val_2):
                    if(items == pred):

...or, if we eliminate the getter...

            for pred in val["predecessor"]:
                for items in val_2["setid_hash"]:
                    if(items == pred):

...could be replaced by a set operation such as:

            if not val["predecessor"].isdisjoint(val_2["setid_hash"]):