擅长:python、mysql、java
<p>正如这个答案中建议的-<a href="https://stackoverflow.com/questions/5188792/how-to-check-a-string-for-specific-characters">How to check a string for specific characters?</a></p>
<pre><code>def is_valid(dna)
if 'A' or 'T' or 'G' or 'C' in dna:
return True
else:
return False
</code></pre>