How to combine a bitcoin dataset and google into one dataframe as following?

Question

Would you please tell me how to correct the following? When I run it, the error appears.

ValueError: Index contains duplicate entries, cannot reshape

import datetime
import pandas_datareader.data as web
# set start and end dates
start = datetime.datetime(2018, 2, 15)
end = datetime.datetime(2020, 2, 14)
# extract the closing price data
combined_df = web.DataReader(["BTC-USD","ETH-USD","GOOG"],
"yahoo", start = start, end = end)

Answer 1

import datetime
import pandas as pd
import numpy as np
import yfinance as yf
# pip install yfinance
# updated version of yahoo_datareader

start = datetime.datetime(2018, 2, 15)
end = datetime.datetime(2020, 2, 14)
symbols = ['BTC-USD', 'ETH-USD', 'GOOG']

df = pd.DataFrame()

for i in symbols:
    data = yf.download(i, start, end)
    df[i] = data['Adj Close']


df = df.fillna(method='ffill')

ind = list(df.index)

df.index = list(range(len(df.index)))
for i in df.index: 
    if df['GOOG'].iloc[i] == 0: 
        df['GOOG'].iloc[i] = df['GOOG'].iloc[i-1]

changes = []
for i in df.index:
    if i == 0:
        changes.append(0.)
    else:
        current = df['GOOG'].iloc[i]
        previous = df['GOOG'].iloc[i-1]
        perc_change = np.round(((current - previous) / previous)*100),2)
        changes.append(perc_change)

df['% Change'] = changes

df.index = ind