Merging and adding multiple dictionaries in Python-CodePudding

I have a dictionary for each state in the continental US. Each has a key-value pair that I have to ultimately merge and add into a single key-value pair. It looks like this:

Indiana = {Year:2018, Total:102 Year:2017, Total: 84....}

Alabama = {Year:2018, Total: 115 Year: 2017, Total:116....}

Colorado = {Year:2018, Total: 71 Year:2017, Total: 76....}

What I want is to merge the dictionaries like this:

Continentals = {Year:2018, Total: 102 115 71 Year: 2017, Total: 84 116 76.....}

Is there a way to merge all these dictionaries into one dictionary while also summing the totals for each year together?

CodePudding user response：

The dictionaries you've provided would overwrite their own values with each entry. You would need to rearrange your dictionary structure to be closer to:

indiana = {2018: total_value, 2017: total_value}
alabama = {2018: total_value, 2017: total_value}
...

This way you could simply loop through your list of state dicts and update a new dict as you iterate.

continentals = {}
for state in list_of_states:
    for year, total_value in state.items():
        continentals[year] = continentals.get(year, 0)   total_value

CodePudding user response：

Using Jesse's structure proposition, you can even do this with a Counter:

from collections import Counter

indiana = {2018: total_value, 2017: total_value}
alabama = {2018: total_value, 2017: total_value}

c = Counter()
for d in[indiana, alabama]:
    c.update(d)