How to extract selected key and value from nested dictionary object in a list? - python-3.x

Question

I have a list example_list contains two dict objects, it looks like this:
[
{
"Meta": {
"ID": "1234567",
"XXX": "XXX"
},
"bbb": {
"ccc": {
"ddd": {
"eee": {
"fff": {
"xxxxxx": "xxxxx"
},
"www": [
{
"categories": {
"ppp": [
{
"content": {
"name": "apple",
"price": "0.111"
},
"xxx: "xxx"
}
]
},
"date": "A2020-01-01"
}
]
}
}
}
}
},
{
"Meta": {
"ID": "78945612",
"XXX": "XXX"
},
"bbb": {
"ccc": {
"ddd": {
"eee": {
"fff": {
"xxxxxx": "xxxxx"
},
"www": [
{
"categories": {
"ppp": [
{
"content": {
"name": "banana",
"price": "12.599"
},
"xxx: "xxx"
}
]
},
"date": "A2020-01-01"
}
]
}
}
}
}
}
]
now I want to filter the items and only keep "ID": "xxx" and the correspoding value for "price": "0.111", expected result can be something similar to :
[{"ID": "1234567", "price": "0.111"}, {"ID": "78945612", "price": "12.599"}]
or something like {"1234567":"0.111", "78945612":"12.599" }
Here's what I've tried:
map_list=[]
map_dict={}
for item in example_list:
#get 'ID' for each item in 'meta'
map_dict['ID'] = item['meta']['ID']
# get 'price'
data_list = item['bbb']['ccc']['ddd']['www']
for data in data_list:
for dataitem in data['categories']['ppp']
map_dict['price'] = item["content"]["price"]
map_list.append(map_dict)
print(map_list)
The result for this doesn't look right, feels like the item isn't iterating properly, it gives me result:
[{"ID": "78945612", "price": "12.599"}, {"ID": "78945612", "price": "12.599"}]
It gave me duplicated result for the second ID but where is the first ID?
Can someone take a look for me please, thanks.
Update:
From some comments from another question, I understand the reason for the output keeps been overwritten is because the key name in the dict is always the same, but I'm not sure how to fix this because the key and value needs to be extracted from different level of for loops, any help would be appreciated, thanks.

Answer 1

as #Scott Hunter has mentioned, you need to create a new map_dict everytime you are trying to do this. Here is a quick fix to your solution (I am sadly not able to test it right now, but it seems right to me).
map_list=[]
for item in example_list:
# get 'price'
data_list = item['bbb']['ccc']['ddd']['www']
for data in data_list:
for dataitem in data['categories']['ppp']:
map_dict={}
map_dict['ID'] = item['meta']['ID']
map_dict['price'] = item["content"]["price"]
map_list.append(map_dict)
print(map_list)
But what are you doing here is that you are basically just "forcing" your way through ... I recommend you to take a break and check out somekind of tutorial, which will help you to understand how it really works in the back-end. This is how I would have written it:
list_dicts = []
for example in example_list:
for www in item['bbb']['ccc']['ddd']['www']:
for www_item in www:
list_dicts.append({
'ID': item['meta']['ID'],
'price': www_item["content"]["price"]
})
Good luck with this problem and hope it helps :)

Answer 2

You need to create a new dictionary for map_dict for each ID.