title: Load compressed data (.npz) from file using numpy.load
body: <p>I have an array:</p>
  
  <pre><code>&gt;&gt;&gt; data = np.ones((1,3,128))
  </code></pre>
  
  <p>I save it to file using <code>savez_compressed</code>:</p>
  
  <pre><code>&gt;&gt;&gt; with open('afile','w') as f:
          np.savez_compressed(f,data=data)
  </code></pre>
  
  <p>When I try to load it I don't seem to be able to access the data:</p>
  
  <pre><code>&gt;&gt;&gt; with open('afile','r') as f:
          b=np.load(f)
  &gt;&gt;&gt; b.files
  ['data']
  &gt;&gt;&gt; b['data']
  
  Traceback (most recent call last):
    File "&lt;pyshell#196&gt;", line 1, in &lt;module&gt;
      b['data']
    File "C:\Python27\lib\site-packages\numpy\lib\npyio.py", line 238, in __getitem__
      bytes = self.zip.read(key)
    File "C:\Python27\lib\zipfile.py", line 828, in read
      return self.open(name, "r", pwd).read()
    File "C:\Python27\lib\zipfile.py", line 853, in open
      zef_file.seek(zinfo.header_offset, 0)
  ValueError: I/O operation on closed file
  </code></pre>
  
  <p>Am I doing something obviously wrong?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>Following  @Saullo Castro's answer I tried this:</p>
  
  <pre><code>&gt;&gt;&gt; np.savez_compressed('afile.npz',data=data)
  &gt;&gt;&gt; b=np.load('afile.npz')
  &gt;&gt;&gt; b.files
  ['data']
  &gt;&gt;&gt; b['data']
  </code></pre>
  
  <p>and got the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;pyshell#253&gt;", line 1, in &lt;module&gt;
      b['data']
    File "C:\Python27\lib\site-packages\numpy\lib\npyio.py", line 241, in __getitem__
      return format.read_array(value)
    File "C:\Python27\lib\site-packages\numpy\lib\format.py", line 440, in read_array
      shape, fortran_order, dtype = read_array_header_1_0(fp)
    File "C:\Python27\lib\site-packages\numpy\lib\format.py", line 336, in read_array_header_1_0
      d = safe_eval(header)
    File "C:\Python27\lib\site-packages\numpy\lib\utils.py", line 1156, in safe_eval
      ast = compiler.parse(source, mode="eval")
    File "C:\Python27\lib\compiler\transformer.py", line 53, in parse
      return Transformer().parseexpr(buf)
    File "C:\Python27\lib\compiler\transformer.py", line 132, in parseexpr
      return self.transform(parser.expr(text))
    File "C:\Python27\lib\compiler\transformer.py", line 124, in transform
      return self.compile_node(tree)
    File "C:\Python27\lib\compiler\transformer.py", line 159, in compile_node
      return self.eval_input(node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 194, in eval_input
      return Expression(self.com_node(nodelist[0]))
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 578, in testlist
      return self.com_binary(Tuple, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 596, in test
      then = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 610, in or_test
      return self.com_binary(Or, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 615, in and_test
      return self.com_binary(And, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 619, in not_test
      result = self.com_node(nodelist[-1])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 626, in comparison
      node = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 659, in expr
      return self.com_binary(Bitor, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 663, in xor_expr
      return self.com_binary(Bitxor, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 667, in and_expr
      return self.com_binary(Bitand, nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 1082, in com_binary
      return self.lookup_node(n)(n[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 671, in shift_expr
      node = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 683, in arith_expr
      node = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 695, in term
      node = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 715, in factor
      node = self.lookup_node(nodelist[-1])(nodelist[-1][1:])
    File "C:\Python27\lib\compiler\transformer.py", line 727, in power
      node = self.com_node(nodelist[0])
    File "C:\Python27\lib\compiler\transformer.py", line 805, in com_node
      return self._dispatch[node[0]](node[1:])
    File "C:\Python27\lib\compiler\transformer.py", line 739, in atom
      return self._atom_dispatch[nodelist[0][0]](nodelist)
    File "C:\Python27\lib\compiler\transformer.py", line 754, in atom_lbrace
      return self.com_dictorsetmaker(nodelist[1])
    File "C:\Python27\lib\compiler\transformer.py", line 1214, in com_dictorsetmaker
      assert nodelist[0] == symbol.dictorsetmaker
  AssertionError
  </code></pre>
  
  <p><strong>EDIT 2</strong></p>
  
  <p>The above error was in IDLE. It worked using Ipython.</p>