Someone help me understand the square bracket in the following Python code?
<pre><code>import xlrd
book = xlrd.open_workbook("univ_list.xls")
sh = book.sheet_by_index(0)
for r in range(sh.nrows)[1:]: # line 4
    print sh.row(r)[:4] # line 5
</code></pre>

<p>What does <code>[1:]</code> mean in line 4? What does <code>[:4]</code> mean in line 5?</p>
