title: python: how to change the value of function's input parameter?
body: <p>I tried to modify the value of a string inside a function, like below:</p>
  
  <pre><code>&gt;&gt;&gt; def appendFlag(target, value):
  ...     target += value
  ...     target += " "
  ...
  &gt;&gt;&gt; appendFlag
  &lt;function appendFlag at 0x102933398&gt;
  &gt;&gt;&gt; appendFlag(m,"ok")
  &gt;&gt;&gt; m
  ''
  </code></pre>
  
  <p>Well, seems the "target" is only changed within the function, but how to make the new value viable outside the function? Thanks.</p>