用于格式化 pandas dataframe 的循环

Question

this is my first post to apologies for any mistakes in my question. I have only recently started to learn to code (since the beginning of quarantine lol.)

I am trying to automate the manipulation of a pandas dataframe

    # First I get the data for my etf
    SOXX = web.DataReader('SOXX', 'yahoo', start, end)

    # I now want to do the following to it
    SOXX = pd.DataFrame(SOXX['Adj Close'])
    SOXX.columns = ['SOXX']

I have tried for loops, cant get them to work. Tried defining a function, didn't work either!

What I would really like to do is, pass in a list of etf names, have it download all the data for each etf in the list and format each etf in the way I want in a single loop.

Answer 1

If I am looking to manipulate a column with some kind of function, I will use a pandas function called apply. See example below:

from yahoo_fin import stock_info as si
import pandas as pd

data = {'Symbol':['GOOG','AAPL'], } 

# Create DataFrame 
df = pd.DataFrame(data) 

def applyFunction(row):
    return si.get_live_price(row['Symbol'])

df['stockPrice'] = df.apply(applyFunction, axis=1) #axis=1 for column apply

Final table would look like

Symbol | stockPrice
GOOG     XXXX.XX
AAPL     XXXX.XX

Hope that helps!