字典映射数组

Question

i want to multiply data inside of array in dictionary. Here's the data.

data = [
  {"data_1": 2, "data_2": 2, "country": "France"},
  {"data_1": 4, "data_2": 4, "country": "UK"},
  {"data_1": 6, "data_2": 6, "country": "USA"},
]

And multiply the data_1 to 5 so the data is like

data = [
  {"data_1": 10, "data_2": 2, "country": "France"},
  {"data_1": 20, "data_2": 4, "country": "UK"},
  {"data_1": 30, "data_2": 6, "country": "USA"},
]

I know the clue is using map, or lambda function. But I have no idea how to do it. Thank you.

Answer 1

One liner:

for d in data: 
    d['data_1'] *= 5

Output:

[{'country': 'France', 'data_1': 10, 'data_2': 2},
 {'country': 'UK', 'data_1': 20, 'data_2': 4},
 {'country': 'USA', 'data_1': 30, 'data_2': 6}]

Answer 2

def m5(hash):
    hash['data_1'] *= 5
    return hash

data2 = list(map(m5, data))

Lambdas are pure functions and as such don't allow assignment, so what you need is to supply a normal function to map().