How can I use i in loop to make variance? : <p>How can I change this code</p>

<pre><code>train_0.append(0)
train_1.append(1)
train_2.append(2)
train_3.append(3)
</code></pre>

<p>using loop like under?</p>

<pre><code>for i in range(4):
    train_i.append(i)
</code></pre>

<p>My code occurs this error.</p>

<pre><code>NameError: name 'train_i' is not defined
</code></pre>

<p>Thank you.</p>
