问题
I have this parameter
x = [{'id': 1L}, {'id': 4L}]
My list contains dicts that contain long integers, so there is a need to convert them to integers.
I want to save only values of id in a new list like
y = [1, 4]
Do you know how to do this?
回答1:
You can use a list comprehension:
ids = [y['id'] for y in x]
This assumes that every dictionary has a key 'id'. If you're not sure that key exists in every dictionary, you can use this one:
ids = [y['id'] for y in x if 'id' in y]
回答2:
I think you want:
[a["id"] for a in x]
回答3:
You can use itemgetter from operator:
y = list(map(itemgetter('id'), x))
来源：https://stackoverflow.com/questions/37463569/extract-dict-value-from-list-of-dict