将列表的字典转换为字典列表

Question

I have a dictionary like so:

{
    "var1": [0, 1],
    "var2": ["foo", "bar"]
}

Given the above, I want to end up with a list of dictionaries like so:

[
    { "var1_0_var2_foo": {"var1": 0, "var2": "foo"} },
    { "var1_1_var2_bar": {"var1": 1, "var2": "bar"} }
]

The number of keys and elements in each list in the original dictionary is variable and can be anything.

Here's my messy looking but working solution:

source = {
    'x': ['a', 'b'],
    'y': [0, 1],
    'z': ['foo', 'bar']
}

target = []


names = list(source.keys())
lists = list(source.values())
zipped = list(zip(*lists))

for item in zipped:
    full_name = ""
    full_dict = {}
    for idx, value in enumerate(item):
        full_name += f"{names[idx]}_{value}_"
        full_dict[names[idx]] = value
    full_name = full_name.rstrip('_')
    target.append({full_name: full_dict})

print(target)

Output:

[
    {'x_a_y_0_z_foo': {'x': 'a', 'y': 0, 'z': 'foo'}}, 
    {'x_b_y_1_z_bar': {'x': 'b', 'y': 1, 'z': 'bar'}}
]

The above works, but I was wondering if there's a better elegant pythonic way of doing this?

Answer 1

from itertools import chain

spam = {'x': ['a', 'b'],
        'y': [0, 1],
        'z': ['foo', 'bar']}

eggs = []
for item in zip(*spam.values()):
    key = '_'.join(chain(*zip(spam.keys(), map(str, item))))
    eggs.append({key:dict(zip(spam.keys(), item))})

print(eggs)

output

[{'x_a_y_0_z_foo': {'x': 'a', 'y': 0, 'z': 'foo'}},
 {'x_b_y_1_z_bar': {'x': 'b', 'y': 1, 'z': 'bar'}}]

Answer 2

I don't understand what the reason for the outer dicts in the output list why not just a list of dict output:

data = {
'var1': [0, 1],
'var2': ["foo", "bar"]}

output = [dict(zip(data, vars)) for vars in zip(*data.values())]

---

[{'var1': 0, 'var2': 'foo'}, {'var1': 1, 'var2': 'bar'}]

Answer 3

Here is a pythonic way to do this with list comprehension and lambda functions -

d = {
    'x': ['a', 'b'],
    'y': [0, 1],
    'z': ['foo', 'bar']
}

f = lambda x: {i:j for i,j in zip(d,x)}  #Creates the values of final output
g = lambda x: '_'.join([str(j) for i in zip(d,x) for j in i])  #Creates the keys of final output

target = [{g(i):f(i)} for i in zip(*d.values())]
print(target)

[{'x_a_y_0_z_foo': {'x': 'a', 'y': 0, 'z': 'foo'}},
 {'x_b_y_1_z_bar': {'x': 'b', 'y': 1, 'z': 'bar'}}]