擅长:python、mysql、java
<p>可以使用itertools中的<code>collections.Counter</code>、和<code>repeat</code>和<code>chain</code>,例如:</p>
<pre><code>from itertools import chain, repeat
from operator import itemgetter
from collections import Counter
junctions = [2,9,15,20]
seq_1 = 'sauron'
seq_2 = 'corrupted'
seq_3 = 'numenor'
indices = list(chain.from_iterable(repeat(i, len(j)) for i, j in enumerate([seq_1, seq_2, seq_3], start=1)))
print Counter(itemgetter(*junctions)(indices))
# Counter({3: 2, 1: 1, 2: 1})
</code></pre>