text: import numpy as np 
  
  
  
  def minmax(x):
  	'''
  	x m*1
  	'''
  	min_ = np.min(x)
  	max_ = np.max(x)
  	x_ = np.zeros_like(x,dtype=float)
  	for i in range(x.shape[0]):
  		x_[i] = (x[i] - min_) / (max_ - min_) 
  	return x_ 
  
  
  if __name__ == "__main__":
  	X = np.array([0, 15, -9, 7, 12, 3, -21])
  	print(minmax(X))