my list of dictionaries is not correctly filled

I’m trying to work with a list of dictionaries and I have a problem.

Here is my code:

for i in range(len(self.dict_trie_csv_infos)):
            self.template_json.append(self.template_json[0])
            #add values to json

for i in range(len(self.dict_trie_csv_infos)):
        self.template_json[i]['id'] = self.dict_trie_csv_infos[i]['id']
        print(self.template_json[i]['id'])
        self.template_json[i]['name'] = self.dict_trie_csv_infos[i]['name']
        self.template_json[i]['title'] = self.dict_trie_csv_infos[i]['event title']
        self.template_json[i]['startDateTime'] = self.dict_trie_csv_infos[i]

        #fill the smart contract now
        self.template_json[i]['ticketCollection'][0]['collectionName'] = self.dict_trie_csv_infos[i]['smart_contract']['collectionName']
        self.template_json[i]['ticketCollection'][0]['endTime'] = self.dict_trie_csv_infos[i]['smart_contract']['sale_params']['end_time']                
        self.template_json[i]['ticketCollection'][0]['pricePerToken'] = self.dict_trie_csv_infos[i]['smart_contract']['sale_params']['price_per_token']
        self.template_json[i]['ticketCollection'][0]['totalTicketsCount'] = ''             
        self.template_json[i]['ticketCollection'][0]['soldTicketsCount'] = ''

print(self.template_json[0])

The first print prints 1 then 2, then 3… but self.template_json[0] prints my last element
and print(self.template_json) it gives me the same result every time.

{'id': '4', 'name': 'Stade de France', 'title': 'Coldplay World Tour', 'startDateTime': 1651615200, 'endDateTime': 1659045600, 'address': '', 'locationName': '93200 Saint-Denis', 'totalTicketsCount': '10000', 'assetUrl': 'https://coldplay.com/coldplay_asset.mp4', 'lineup': [''], 'ticketCollection': [{'collectionName': 'KT2jH58CPkYBe3bRuTCET6A4NhnosX2BAnp9', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': 50, 'maxMintPerUser': '', 'saleSize': '', 'endTime': 1659045600, 'totalTicketsCount': '', 'soldTicketsCount': ''}], 'adress': 'KT1ffDxCJH9EPimNm19ifBEgG9bFRgptJwop'}

there is my template_json before the loop:

[{'id': '', 'name': '', 'title': '', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}, {'id': '', 'name': '', 'title': 
'', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}, {'id': '', 'name': '', 'title': '', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}, {'id': '', 'name': '', 'title': '', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}, {'id': '', 'name': '', 'title': '', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}, {'id': '', 'name': '', 'title': '', 'startDateTime': '', 'endDateTime': '', 'address': '', 'locationName': '', 'totalTicketsCount': '', 'assetUrl': '', 'lineup': [], 'ticketCollection': [{'collectionName': '', 'scAddress': '', 'collectionAddress': '', 'pricePerToken': '', 'maxMintPerUser': '', 'saleSize': ''}]}]

and there is my "print(self.dict_tries_csv):

{'event_id': 1, 'collection_name': 'Mouse On', 'smart_contract': {'multisig': 'KT1Aer6TxNwoMJejoqsNP8TEN7J6STgMtJcA', 'sale_params': {'is_presale': False, 'metadata_list': [], 'price_per_token': 4, 'max_mint_per_user': 5, 'sale_size': 500, 'sale_currency': {'xtz': None}, 'start_time': 1656626400, 'end_time': 1657490400}, 'collectionName': 'KT1Apf8CPkYBe3bRuTCET6A4NhnosX2BAnp9', 'scAddress': 'KT1AKqxCJH9EPimNm1wo1BEgG9bFRgptJwkk'}, 'id': '1', 'event title': 'Mouse Party', 'event start date': '10/07/2022 18:30', 'event end date': '11/07/2022 01:00', 'name': "L'Astrolabe", 'address of the location': '1 Rue Alexandre Avisse 45000 Orléans', 'total ticket number': '500', 'maximum tickets per user': '5', 'sale start date': '01/07/2022', 'line up': 'Mehdi Maïzi-Rad Cartier-Squidji', 'asset url': 'https://photos.com/mouseparty.png', 'lineup': ['Mehdi Maïzi', 'Rad Cartier', 'Squidji']}

I expected to get id == 1

>Solution :

All your list elements are the same dictionary. You need to copy them.

from copy import deepcopy

for i in range(len(self.dict_trie_csv_infos)):
    self.template_json.append(deepcopy(self.template_json[0]))