如何修复 python 中的字典 get() 方法“列表索引超出范围”

Question

I execute a url request substituting values into it and get data in the following format

{'retCode': 0, 'retMsg': 'OK', 'result': {'category': 'linear', 'list': [{'symbol ': 'XRPUSDT', 'bidPrice': '0.4089'}]}}

and I need to get bidprice from it, I use the get() method so that in case of an error

(lack of value in the url)

I save the value None, but I get the error

list index out of range

json.get('result', {}).get('list', {})[0].get('lastPrice')

Answer 1

There are 3 problems I can see:

1. Don't use json as a variable name because it's a standard lib
2. You look for the first element of a list which can be empty
3. Your second 'get' return a dictionary if there is no key called 'list' in the dictionary 'result'.

Here is a solution:

    def get_bid_price(json_returned):
        result_list = json_returned.get('result', {}).get('list', [{}])
        if result_list:
            return result_list[0].get('bidPrice')

Answer 2

On the basis of the dictionary structure shown in the question you probably want:

print(_dict.get('result', {}).get('list', [{}])[0].get('lastPrice'))

Note the change to the default when getting 'list'