如何使用 Panda 和 Numpy 从 Excel 中正确切片数据？

Question

When I try to import data from Excel using pandas and NumPy, I get the error shown below.

...

import pandas as pd
import numpy as np
# Importing prostate data
prostate_data = pd.read_excel(r'C:\Users\shrey\Documents\BIOE 594\prostate_dat.xlsx')
data = pd.DataFrame(prostate_data, columns= ['lcavol','lweight','age','lbph',
                                             'svi','lcp','gleason','pgg45','lpsa'])
data.to_numpy()

A = data[:,0:7]
b = data[:,8]
At= np.transpose(A)
y = np.linalg.inv(At*A) # Estimating parameter using normal equation
x = y * (At*b)
print(x)
...

Error: TypeError: '(slice(None, None, None), slice(0, 7, None))' is an invalid key

Answer 1

You didn't re-assign the numpy array you created, so the dataframe wasn't transformed. Use:

data = data.to_numpy()