如何从 python 中的 dataframe 中提取数据（索引）

Question

I am trying to take the feature but not getting the results.

df_close = df['Close']
df_train = df_close[:'2019-12-31']
df_train.shape

training_set = df_close
from sklearn.preprocessing import MinMaxScaler
sc = MinMaxScaler(feature_range = (0, 1))
training_set_scaled = sc.fit_transform(training_set)
training_set_scaled[1]

import numpy as np
X_train = []
y_train = []
for i in range(100, training_set.shape[1]): 
  X_train.append(training_set_scaled[i-100:i, 0]) 
  y_train.append(training_set_scaled[i, 0]) 
X_train, y_train = np.array(X_train), np.array(y_train)
X_train

and the result is:

array([], dtype=float64)

Answer 1

If the value of training_set.shape[1] is smaller then 100 then the inside of the for loop is skipped, leaving X_train empty.

You could test this case by adding a print statement inside the for loop. Let me know if it worked, good luck!