<p>您可以使用<a href="https://docs.python.org/3/library/functions.html?highlight=any#any" rel="nofollow noreferrer">^{<cd1>}</a>检查是否有任何字母(对于字符串中的字母)以<code>InputSequence</code>小写<a href="https://docs.python.org/3/library/stdtypes.html?highlight=lower#str.lower" rel="nofollow noreferrer">^{<cd3>}</a>的形式出现</p>
<pre><code>validationcheck = False
while not validationcheck:
InputSequence = input("Input: ")
if (InputSequence == 'EXAMPLE':
validationcheck = True
elif not len(InputSequence) % 3 and any(i in InputSequence.lower() for i in 'tgac'):
validationcheck = True
else:
print("Invalid input")
InputSequence = input("Input: ")
</code></pre>
<p>您还可以使用正则表达式搜索输入是否仅包含字符“t”、“g”、“a”或“c”</p>
<pre><code>import re
validationcheck = False
while not validationcheck:
InputSequence = input("Input: ")
if (InputSequence == 'EXAMPLE':
validationcheck = True
elif not len(InputSequence) % 3 and re.fullmatch(r'[tgac]+[\r\n]*', InputSequence.lower()):
validationcheck = True
else:
print("Invalid input")
InputSequence = input("Input: ")
</code></pre>
<p>正则表达式<code>[tgac]+[\r\n]*</code>表示“t'或'g'或'a'或'c'中的一个1或无限次,然后行分隔(可以是'\n','\r','\r\n')0或无限次”<a href="https://docs.python.org/3/library/re.html?highlight=re#module-re" rel="nofollow noreferrer">more about regex</a></p>