How to fill missing values in a list that belong to another list using Python?

Question

Considering having this type of lists:

month_list = ['Mar', 'Aug', 'Okt', 'Nov']
value_for_each_month = [4, 10, 8, 5]

So, each value belongs to the month in the month_list, e.g. 'Mar' --> 4, 'Aug' --> 10 and so on..

Now, how to fill both lists in Python to achieve this result:

month_list_new = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
value_for_each_month_new = [0, 0, 4, 0, 0, 0, 0, 10, 0, 8, 5, 0]

But, what is the criteria for the match. What is the logic with Mar pointing to 10 and Aug pointing to 8. This makes no sense. — idjaw
– idjaw, Commented Jul 22, 2017 at 12:40
Each index of the month_list matches the index in the value_for_each_month list. That is the criteria, I thought it was clear enough.. — Pythonic
– Pythonic, Commented Jul 22, 2017 at 12:41
You just changed your question to have it make sense now. It wasn't like that before. — idjaw
– idjaw, Commented Jul 22, 2017 at 12:43
Can you show your code to see what challenges your facing in your implementation? — idjaw
– idjaw, Commented Jul 22, 2017 at 12:44

tobias_k · Accepted Answer · 2017-07-22 12:49:52Z

2

Create a dictionary mapping month names to values...

>>> month_list = ['Mar', 'Aug', 'Okt', 'Nov']
>>> value_for_each_month = [4, 10, 8, 5]
>>> month_values = dict(zip(month_list, value_for_each_month))
>>> month_values
{'Aug': 10, 'Mar': 4, 'Nov': 5, 'Okt': 8}

... than use that dict in a list comprehension:

>>> month_list_new = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']    
>>> value_for_each_month_new = [month_values.get(m, 0) for m in month_list_new]
>>> value_for_each_month_new
[0, 0, 4, 0, 0, 0, 0, 10, 0, 0, 5, 0]

answered Jul 22, 2017 at 12:49

tobias_k

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