title: Python how to assign values to a certain row of a matrix?
body: <p>In Python, </p>
  
  <p>I created a 10 x 20 zero-matrix, called X:
  X = numpy.zeros((10, 20))</p>
  
  <p>I have another 50 x 20 matrix called A.  </p>
  
  <p>I want to let the 4th row of matrix X take the value of the 47th row of matrix A. </p>
  
  <p>How can I write this in Python? </p>
  
  <p>Note: if X is a list, then I could just write X.append ()   However, here X is not a list...then how can I do this? </p>
  
  <p>Or, if I just have a list that contains 20 numbers, how can I let the 4th row of matrix X equal to that list of 20 numbers? </p>
  
  <p>Thank you!</p>