擅长:python、mysql、java
<p>创建一个字典(counts),然后检查该字母是否在字典中。如果是,则增加值(+=),否则将值初始化为1。然后打印结果。你知道吗</p>
<pre><code>dna = 'AGGTCCCAATGA'
counts = {}
for nucleotide in dna:
if nucleotide in counts:
counts[nucleotide] += 1
else:
counts[nucleotide] = 1
for nucleotide in counts:
print(f'{nucleotide} occurs {counts[nucleotide]} times')
</code></pre>
<p>结果:</p>
<pre><code>A occurs 4 times
G occurs 3 times
T occurs 2 times
C occurs 3 times
</code></pre>