python dict key in list to filter

a = [{"price": 1,"id": 1},{"price": 8.2, "id": 2}, {"price": 10.99,"id": 3}]

user = ['price', 'abc']

output supposed to be:

output = [{"price": 1},{"price": 8.2}, {"price": 10.99}]

The scenario is that dict a keys should be filtered by user list

CodePudding user response：

You can use list comprehension

[{u: val_a.get(u) for u in user if val_a.get(u)} for val_a in a]

Nested comprehensions may not be desirable and the above example checks twice for the value. Building your results by a loop may give the most straightforward result and be readable at the same time:

results = []
for val_a in a:
    result = {}
    for u in user:
        u_val = val_a.get(u)
        if u_val:
            result.update({u: u_val})
    results.append(result)

Python3.8 :

results = []
for val_a in a:
    result = {}
    for u in user:
        if u_val := val_a.get(u)
            result.update({u: u_val})
    results.append(result)

CodePudding user response：

You can use a set intersection operation to get the keys to retain:

result = [{k: d[k] for k in set(d.keys()).intersection(set(user))} for d in a]
print(result)

This prints:

[{'price': 1}, {'price': 8.2}, {'price': 10.99}]