如何使用 api 和 for 循环组合来自 json 文件的多个数据帧？ （Python）

Question

I am trying to download financial ratio data for more than one company ticker and save the data to one data frame. I have used a function to interact with the API and download the json file, then I am trying to make a for loop to iterate through the dictionary of tickers.

api_key = 'API KEY REMOVED FOR PRIVACY'

def get_ratios(stock):
    url = (f'https://financialmodelingprep.com/api/v3/ratios/{stock}?limit=40&apikey={api_key}')
    x = pd.read_json(url)
    return x

Using just the function get_ratios('AAPL') returns a dataframe, but I want to be able to retrieve data for multiple tickers, not just AAPL. I have tried to create a for loop to be able to retrieve data for multiple tickers. When I try save the function to a dataframe only the data for AAN saves.. so I think it must be overwriting the data for AAPL. I am unsure how to fix this, I have tried to create another for loop to .append the dataframe y to itself, but I just get an error back.

ticker = ['AAPL','AAN']
for i in ticker:
    y = get_ratios(i)

But when I don't save get_ratios(i) to a list and run it as shown below, I get a list of both AAPL and AAN data.

ticker = ['AAPL','AAN']
for i in ticker:
    print(get_ratios(i))

symbol date period currentRatio quickRatio cashRatio
0 AAPL 2020-09-26 FY 1.363604 1.218195 0.360710
1 AAPL 2019-09-28 FY 1.540126 1.384447 0.462022
2 AAPL 2018-09-29 FY 1.123843 0.986566 0.221733
3 AAPL 2017-09-30 FY 1.276063 1.089670 0.201252

Answer 1

Put the dataframes returnet by get_ratios() to a list and as a final step do pd.concat to concat the dataframes to one. For example:

ticker = ["AAPL", "AAN"]

df_list = []
for i in ticker:
    df_list.append(get_ratios(i))

df_final = pd.concat(df_list)

Answer 2

在使用列表理解和pd.concat ，您可以执行以下操作：

df = pd.concat([get_ratios(t) for t in ticker])