擅长:python、mysql、java
<pre><code>import csv
with open('x.txt') as f:
# use space as delimiter
reader = csv.reader(f, delimiter=' ')
# sort by the value in the second place of each line i.e. x[1]
s = sorted(reader, key=lambda x: x[1], reverse=True)
# filter only grater than 0.5 and take the first value only
l = [x[0] for x in s if float(x[1])>0.5]
print l[:3]
print l[3:]
</code></pre>