file access peek ahead
<p>I need to read a file, line by line and I need to peek into 'the next line' so first I read the file into a list and then I cycle throught the list... somehow this seems rude, building the list could be become expensive.</p>

<pre><code>for line in open(filename, 'r'):
    lines.append(line[:-1])

for cn in range(0, len(lines)):
    line = lines[cn]
    nextline = lines[cn+1] # actual code checks for this eof overflow
</code></pre>

<p>there must be a better way to iterate over the lines but I don't know how to peek ahead</p>
