title: replacing text in a file with Python
body: <p>I'm new to Python. I want to be able to open a file and replace every instance of certain words with a given replacement via Python.  as an example say replace every word 'zero' with '0', 'temp' with 'bob', and say 'garbage' with 'nothing'.</p>
  
  <p>I had first started to use this:</p>
  
  <pre><code>for line in fileinput.input(fin):
          fout.write(line.replace('zero', '0'))
          fout.write(line.replace('temp','bob'))
          fout.write(line.replace('garbage','nothing'))
  </code></pre>
  
  <p>but I don't think this is an even remotely correct way to do this.  I then thought about doing if statements to check if the line contains these items and if it does, then replace which one the line contains, but from what I know of Python this also isn't truly an ideal solution.  I would love to know what the best way to do this.  Thanks ahead of time!</p>