Python 3.5 iterate through a list of dictionaries

Question

My code is

index = 0
for key in dataList[index]:
    print(dataList[index][key])

Seems to work fine for printing the values of dictionary keys for index = 0.

But for the life of me I can't figure out how to put this for loop inside a for loop that iterates through the unknown number of dictionaries in dataList

Answer 1

You can easily do this:

for dict_item in dataList:
  for key in dict_item:
    print dict_item[key]

It will iterate over the list, and for each dictionary in the list, it will iterate over the keys and print its values.

Answer 2

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.