title: How to rewrite the node ids that stored in .mtx file
body: <p>I have a <code>.mtx</code> file that looks like below:</p>
  <pre><code>0 435   1
  0 544   1
  1 344   1
  2 410   1
  2 471   1
  </code></pre>
  <p>This matrix has shape of <code>(1000, 1000)</code>.
  As you can see, node ids starts at <code>0</code>. I want to change this to start at <code>1</code> instead of <code>0</code>.
  In other words, I need to add <code>1</code> to all the numbers in the first and second columns that represent the node ids.</p>
  <p>So I converted <code>.mtx</code> file to <code>.txt</code> file and tried to add <code>1</code> in each first and second columns.</p>
  <p>and simply added <code>1</code> to each row like below</p>
  <pre><code>import numpy as np 
  
  data_path = &quot;my_data_path&quot;
  data = np.loadtxt(data_path, delimiter=' ', dtype='int')
  for i in data:
      print(data[i]+1)
  </code></pre>
  <p>and result was</p>
  <pre><code>[  1 436   2]
  [  1 545   2]
  [  2 345   2]
  [  3 411   2]
  [  3 472   2]
  </code></pre>
  <p>now I need to subtract <code>1</code> from third column, but I have no idea how to implement that.</p>
  <p>Can someone help me to do that?</p>
  <p>Or if there's any way to complete my goal way more easier, please tell me. Thank you in advance.</p>