How do I read data in sub-dictionary in python - json

Question

My problem is that I cannot see the data I pulled from the mongo database separately. The data comes as a dictionary and when I try to read it with pandas, it returns the sub dictionary group as a single data.
import pandas
dic = {
"value1" : "a",
"value2" : {
"subvalue1" : "sub-a",
"subvalue2" : "sub-b"
},
"value3" : "c"
}
df = pandas.DataFrame(dic)
df = pandas.DataFrame(list(dic.items()), columns=["value1","subvalue1"])
print(df)
When I run the code, the output I get is as follows.
value1 subvalue1
0 value1 a
1 value2 {'subvalue1': 'sub-a', 'subvalue2': 'sub-b'}
2 value3 c
Process finished with exit code 0
What I want is I want to produce an output with the values in the "columns" array by writing a code like the one below.
import pandas
dic = {
"value1" : "a",
"value2" : {
"subvalue1" : "sub-a",
"subvalue2" : "sub-b"
},
"value3" : "c"
}
df = pandas.DataFrame(dic)
df = pandas.DataFrame(list(dic.items()), columns=["value1","subvalue1","subvalue2","value3"])
print(df)
output sample I want
How can i do this.
Thank you for all.

Answer 1

you can do that by flattening the dictionary like this:
def flatten_dict(d):
flattened={}
for key, val in d.items():
if isinstance(val,dict):
flattened.update(flatten_dict(val))
else:
flattened.update({key:val})
return flattened
I don't recommend this way however. If you happen to have a dictionary of the form {"a":{"same_key_name":"value_a"}, "b":{"same_key_name":"value_b"}} then the flattened dictionary would be {'same_key_name': 'value_b'}
A safer and more canonical way to do it is to flatten the dictionary but keep the key names in a concatenated form:
df = pd.json_normalize(d, sep='_')