title: How to copy array in Python
body: <p>It seems like a simple question. But for me it is tricky... Sorry.
  I have a big ndarray with shape (2800, 256, 256, 3) which was filled with zeros.
  And I have a ndarray with shape (700, 256, 256, 3) with data. So I want copy data to the first array. In such way that only first 700 rows in the first array will be with data from the second array. So how?</p>