Modify dictionary key

Question

Hi I have a dictionary like below

{
'namelist': [{'name':"John",'age':23,'country':'USA'},
                   {'name':"Mary",'age':12,'country':'Italy'},
                   {'name':"Susan",'age':32,'country':'UK'}],
'classteacher':'Jon Smith'
}

I would like to know is it possible to change it to

 {
 'namelist': [{'name_1':"John",'age_1':23,'country_1':'USA'},
               {'name_2':"Mary",'age_2':12,'country_3':'Italy'},
               {'name_3':"Susan",'age_3':32,'country_3':'UK'}],
 'classteacher':'Jon Smith'
 }

By adding _1, _2 .... on every last position of every key Is it possible? Thank you for your help

Answer 1

You can add the new values in the initial list with changing the key and removing the initial values yourdict[j+'_'+str(num)] = yourdict.pop(j)

keys() returns all the keys of a dict ( name, age, country in your case)

a = {'namelist': [{'name':"John",'age':23,'country':'USA'},
                  {'name':"Mary",'age':12,'country':'Italy'},
                  {'name':"Susan",'age':32,'country':'UK'}]}

num = 1
for i in a['namelist']:
    for j in list(i.keys()):
        i[j+'_'+str(num)] = i.pop(j)
    num += 1

print(a)
# {'namelist': [
#    {'name_1': 'John', 'country_1': 'USA', 'age_1': 23}, 
#    {'name_2': 'Mary', 'country_2': 'Italy', 'age_2': 12}, 
#    {'name_3': 'Susan', 'age_3': 32, 'country_3': 'UK'}]}

Answer 2

Using enumerate

Ex:

d = {'namelist': [{'name':"John",'age':23,'country':'USA'},
               {'name':"Mary",'age':12,'country':'Italy'},
               {'name':"Susan",'age':32,'country':'UK'}]}

d["namelist"] = [{k+"_"+str(i): v for k,v in value.items()} for i , value in enumerate(d["namelist"], 1)]
print(d)  

Output:

{'namelist': [{'age_1': 23, 'country_1': 'USA', 'name_1': 'John'},
              {'age_2': 12, 'country_2': 'Italy', 'name_2': 'Mary'},
              {'age_3': 32, 'country_3': 'UK', 'name_3': 'Susan'}]}

Answer 3

You will have to create new key, with value correspond to old key. You can achieve this easily in one line using dict.pop

I will assume you want to add index of the row into field name . For other fields or modified them in other ways, you can do similarly.

for index, row in enumerate(a['namelist']):
    row['name_%d' % index] = row.pop('name')

Output:

{'namelist': [{'age': 23, 'country': 'USA', 'name_0': 'John'},
  {'age': 12, 'country': 'Italy', 'name_1': 'Mary'},
  {'age': 32, 'country': 'UK', 'name_2': 'Susan'}]}

Answer 4

Here is my one-line style solution, which works even if you have many keys other than 'namelist':

d = {'namelist': [{'name':"John",'age':23,'country':'USA'},
                   {'name':"Mary",'age':12,'country':'Italy'},
                   {'name':"Susan",'age':32,'country':'UK'}],
     'classteacher':'Jon Smith'
    }


d = {k:[{f'{k2}_{nb}':v2 for k2,v2 in i.items()} for nb,i in enumerate(v,1)] if isinstance(v,list) else v for k,v in d.items()}

print(d)
# {'namelist': [{'name_1': 'John', 'age_1': 23, 'country_1': 'USA'},
#               {'name_2': 'Mary', 'age_2': 12, 'country_2': 'Italy'},
#               {'name_3': 'Susan', 'age_3': 32, 'country_3': 'UK'}]}, 
#  'classteacher': 'Jon Smith'
# }

However as Aran-Fey said, this is not really readable and very difficult to maintain. So I also suggest you the solution with nested for loops:

d1 = {'namelist': [{'name':"John",'age':23,'country':'USA'},
                   {'name':"Mary",'age':12,'country':'Italy'},
                   {'name':"Susan",'age':32,'country':'UK'}],
      'classteacher':'Jon Smith'}

for k1,v1 in d1.items():
    if isinstance(v1,list):
        for nb,d2 in enumerate(v1,1):
            for k2 in list(d2):
                d2[f'{k2}_{nb}'] = d2.pop(k2)

print(d1)
# {'namelist': [{'name_1': 'John', 'age_1': 23, 'country_1': 'USA'},
#               {'name_2': 'Mary', 'age_2': 12, 'country_2': 'Italy'},
#               {'name_3': 'Susan', 'age_3': 32, 'country_3': 'UK'}]}, 
#  'classteacher': 'Jon Smith'
# }

Answer 5

You can use dict and list comprehensions:

d = {'namelist': [{'name': "John", 'age': 23, 'country': 'USA'},
              {'name': "Mary", 'age': 12, 'country': 'Italy'},
              {'name': "Susan", 'age': 32, 'country': 'UK'}]}
d = {k: [{'_'.join((n, str(i))): v for n, v in s.items()} for i, s in enumerate(l, 1)] for k, l in d.items()}

d would become:

{'namelist': [{'name_1': 'John', 'age_1': 23, 'country_1': 'USA'}, {'name_2': 'Mary', 'age_2': 12, 'country_2': 'Italy'}, {'name_3': 'Susan', 'age_3': 32, 'country_3': 'UK'}]}

Answer 6

for i, dct in enumerate(inp['namelist'], 1):
    for key, value in list(dct.items()):  # take a copy since we are modifying the dct
        del dct[key]  # delete old pair
        dct[key+'_'+str(i)] = value  # new key format

This would be in place. You are not using extra memory. Iterating over each value inside the dict and then deleting the old key-value pair and adding the it with a change in the key name.

Answer 7

使用字典理解：

    mydictionary['namelist'] = [dict((key + '_' + str(i), value) for key,value in mydictionary['namelist'][i-1].items()) for i in [1, 2, 3]]