从字典列表中提取值基于python3中的另一个值

Question

I have a lists of dictionaries:

list = [
    {'i': 1, 'j': 1, 'diff': 39},
    {'i': 1, 'j': 1, 'diff': 27},
    {'i': 1, 'j': 1, 'diff': 18},
    {'i': 1, 'j': 1, 'diff': 33},
    ...
]

From this, I need to extract the values of i and j for the entry that has the greatest diff .

I've seen a lot of solutions that would simply extract the greatest diff , but that's not what's needed here. And I can think of ways to do this that would involve looping through and comparing each value to the others one by one, but that seems neither efficient nor pythonic.

What's the best way to go about this?

Answer 1

Use max with key argument to specify that you need to find dictionary inside list having maximum value for 'diff' key:

lst = [
    {'i': 1, 'j': 1, 'diff': 39},
    {'i': 1, 'j': 1, 'diff': 27},
    {'i': 1, 'j': 1, 'diff': 18},
    {'i': 1, 'j': 1, 'diff': 33}
]

max_dict = max(lst, key=lambda x: x['diff'])

print(max_dict['i'])  # 1
print(max_dict['j'])  # 1