title: What does a tensorflow "op" do?
body: <p>Below I have created a tf placeholder named &quot;op testing&quot;:</p>
  <pre><code>self.center_words = tf.placeholder(tf.int32, shape=[self.batch_size], name='op testing')
  print(&quot;Extracting the op&quot;, self.center_words.op)
  </code></pre>
  <p>When I print that <strong>self.center_words.op</strong> it prints out a structure like this:</p>
  <pre><code>op: &quot;Placeholder&quot;
  attr {
    key: &quot;dtype&quot;
    value {
      type: DT_INT32
    }
  }
  attr {
    key: &quot;shape&quot;
    value {
      shape {
        dim {
          size: 128
        }
      }
    }
  }
  </code></pre>
  <p>This works for any TensorFlow variable, function output, etc. What is this <em><strong>.op</strong></em>?</p>