title: ValueError and TypeError in python
body: <p>I can't completely understand the difference between Type and Value error in Python3x. </p>
  
  <p>Why do we get a ValueError when I try float('string') instead of TypeError? shouldn't this give also a TypeError because I am passing a variable of type 'str' to be converted into float?</p>
  
  <pre><code>In [169]: float('string')
  ---------------------------------------------------------------------------
  ValueError                                Traceback (most recent call last)
  &lt;ipython-input-169-f894e176bff2&gt; in &lt;module&gt;()
  ----&gt; 1 float('string')
  
  ValueError: could not convert string to float: 'string'
  </code></pre>