title: read binary data using numpy
body: <p>I have a binary file and I wonder how I can read it using <code>numpy</code>. The format of the data is 10 characters of <code>string</code> followed by 100 <code>floats</code> (stored using 4 characters each). I know the following snippet with <code>struct</code> module can solve this, but for large files the struct code is too time-consuming. </p>
  
  <pre><code>f = open(file, 'rb')
  while True:
      tag = f.read(10)
      if tag== '': break
      b = []
      for i in range(100):
        b.append(struct.unpack('f', f.read(4)))
      yield tag, b
  </code></pre>
  
  <p>I'm a little confused with the <code>numpy.fromfile</code>, it seems this can meet my requirement.  </p>