遍历作为字典值的列表

Question

I have many sets of JSON data, each of which looks like this after being converted into dict:

json_data = 
{
  "root":[
    1,
    2,
    3
  ]
}

I want to iterate through the list [1,2,3] with this:

for value in json_data.values():
    print(value)

I expect to get this output:

1 2 3 But I get this:

[1,2,3]

What should I change in the code? Thanks !

Answer 1

dict.keys() or dict.values() will give us dict_values([[1, 2, 3]])

So iterating through this like

for value in json_data.values():
    print(value)

will return us. Note: json_data.values()[0] will return an error TypeError: 'dict_values' object is not subscriptable

[1, 2, 3]

You have three options here.

Option1 use your example but iterate twice

for value in json_data.values():
    for lst in value:
        print(last)

Option2 if you know the key you can use .get() or dict['key']

for value in json_data['root']:
    print(value)

for value in json_data.get('root'):
    print(value)

Option3

for value in json_data.values():
    print(*value)

This will give you 1 2 3 Now of course there are many more options but these are what I could think of.

Answer 2

You probably want to use dict.items() :

json_data = {
    "root": [1, 2, 3]
}

for key, values in json_data.items():
  print(key, values)

  for value in values:
    print(value)

Answer 3

You can use the list key word so that you can use the indices of the json_data.values()

for value in list(json_data.values())[0]:
    print(value)

this will return: (in your example case)

1
2
3

To do this for all the keys in json_data, you can do:

for index in range(len(json_data.values())):
    for value in list(json_data.values())[index]:
        print(value)