I recently began learning Python, but rather with a complex project I had already started in Excel. I have used different guides for the code I have used so far, tweaked to my needs.

I am using 'yfinance' to gather data for multiple cryptocurrencies in a specific time period from Yahoo! Finance. Also, 'stats models' to obtain alpha, beta and r squared using a DataFrame created with all cryptocurrencies and an additional column with the mkt. return (x variable).

I am having the following error: **ValueError: endog and exog matrices are different sizes**. I saw another question/answer regarding this error, but it did not seem to relate to my issue.

The error takes place in line 87 [model = sm.OLS(Y2,X_)] of the following code:

```
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
import datetime
from pandas_datareader import data as pdr
import yfinance as yf
yf.pdr_override()
df1 = pdr.get_data_yahoo("BTC-USD", start="2015-01-01", end="2020-01-01")
df2 = pdr.get_data_yahoo("ETH-USD", start="2015-01-01", end="2020-01-01")
df3 = pdr.get_data_yahoo("XRP-USD", start="2015-01-01", end="2020-01-01")
df4 = pdr.get_data_yahoo("BCH-USD", start="2015-01-01", end="2020-01-01")
df5 = pdr.get_data_yahoo("USDT-USD", start="2015-01-01", end="2020-01-01")
df6 = pdr.get_data_yahoo("BSV-USD", start="2015-01-01", end="2020-01-01")
df7 = pdr.get_data_yahoo("LTC-USD", start="2015-01-01", end="2020-01-01")
df8 = pdr.get_data_yahoo("BNB-USD", start="2015-01-01", end="2020-01-01")
df9 = pdr.get_data_yahoo("EOS-USD", start="2015-01-01", end="2020-01-01")
df10 = pdr.get_data_yahoo("LINK-USD", start="2015-01-01", end="2020-01-01")
df11 = pdr.get_data_yahoo("XMR-USD", start="2015-01-01", end="2020-01-01")
df12 = pdr.get_data_yahoo("BTG-USD", start="2015-01-01", end="2020-01-01")
return_btc = df1.Close.pct_change()[1:]
return_eth = df2.Close.pct_change()[1:]
return_xrp = df3.Close.pct_change()[1:]
return_bch = df4.Close.pct_change()[1:]
return_usdt = df5.Close.pct_change()[1:]
return_bsv = df6.Close.pct_change()[1:]
return_ltc = df7.Close.pct_change()[1:]
return_bnb = df8.Close.pct_change()[1:]
return_eos = df9.Close.pct_change()[1:]
return_link = df10.Close.pct_change()[1:]
return_xmr = df11.Close.pct_change()[1:]
return_btg = df12.Close.pct_change()[1:]
d = {"BTC Return":return_btc, "ETH Return":return_eth, "XRP Return":return_xrp, "BCH Return":return_bch,
"USDT Return":return_usdt, "BSV Return":return_bsv, "LTC Return":return_ltc, "BNB Return":return_bnb,
"EOS Return":return_eos, "LINK Return":return_link, "XMR Return":return_xmr, "BTG Return":return_btg}
df = pd.DataFrame(d) # new data frame with all returns data
df = pd.DataFrame(d, columns=["Date", "BTC Return", "ETH Return", "XRP Return", "BCH Return", "USDT Return", "BSV Return",
"LTC Return", "BNB Return", "EOS Return", "LINK Return", "XMR Return", "BTG Return"])
avg_row = df.mean(axis=1)
return_mkt = avg_row
d1 = {"BTC Return":return_btc, "ETH Return":return_eth, "XRP Return":return_xrp, "BCH Return":return_bch,
"USDT Return":return_usdt, "BSV Return":return_bsv, "LTC Return":return_ltc, "BNB Return":return_bnb,
"EOS Return":return_eos, "LINK Return":return_link, "XMR Return":return_xmr, "BTG Return":return_btg, "MKT Return":return_mkt}
df = pd.DataFrame(d1)
print(df)
import statsmodels.api as sm
from statsmodels import regression
X = return_mkt.values
Y1 = return_btc
Y2 = return_eth
#Y3 = return_xrp
def linreg(x,y):
x = sm.add_constant(x)
model = regression.linear_model.OLS(y,x).fit()
# we are removing the constant
x = x[:, 1]
return model.params[0], model.params[1]
X_ = sm.add_constant(X) # artificially add intercept to x, as advised in the docs
model = sm.OLS(Y1,X_)
results = model.fit()
rsquared = results.rsquared
alpha, beta = linreg(X,Y1)
def linreg(x,y):
x = sm.add_constant(x)
model = regression.linear_model.OLS(y,x).fit()
# we are removing the constant
x = x[:, 1]
return model.params[0], model.params[1]
X_ = sm.add_constant(X) # artificially add intercept to x, as advised in the docs
model = sm.OLS(Y2,X_)
results = model.fit()
rsquared = results.rsquared
alpha, beta = linreg(X,Y2)
```

The error is located in the second **def**, as I am trying to compute the previously mentioned statistics for each cryptocurrency. Thus, the 1st def is for BTC (Y1), the 2nd def is for ETH (Y2), and so on (Y3,...).

The entire code was fine when I had only the function for BTC at the end, the error occurred when I tried to add more of the same function for the others.