擅长:python、mysql、java
<p>正如@Barmar在评论中所说的(他/她评论时我正在键入答案),如果字典的键和值不是变量或数字,则应该将它们括起来:</p>
<pre class="lang-py prettyprint-override"><code>dic_enz = {"EcoRI": "G^AATTC"}
my_seq = "foo1GAATTCfoo2GAATTCfoo3GAATTCfoo4"
first_enz = dic_enz.get('EcoRI')
first_seq = first_enz.replace('^', '')
print(my_seq.count(first_seq))
</code></pre>
<p>输出<code>3</code>。你知道吗</p>