title: Concatenating two one-dimensional NumPy arrays
body: <p>How do I concatenate two one-dimensional arrays in <a href="http://en.wikipedia.org/wiki/NumPy" rel="nofollow noreferrer">NumPy</a>? I tried <a href="https://numpy.org/doc/stable/reference/generated/numpy.concatenate.html" rel="nofollow noreferrer"><code>numpy.concatenate</code></a>:</p>
  <pre><code>import numpy as np
  a = np.array([1, 2, 3])
  b = np.array([4, 5])
  np.concatenate(a, b)
  </code></pre>
  <p>But I get an error:</p>
  <blockquote>
  <p>TypeError: only length-1 arrays can be converted to Python scalars</p>
  </blockquote>