擅长:python、mysql、java
<p>使用<a href="https://docs.python.org/3/library/fractions.html" rel="nofollow noreferrer">fractions library</a>可以执行以下操作:</p>
<pre><code>import fractions
myinput = input("Enter number. ")
try:
if not myinput.isnumeric():
myinput = fractions.Fraction(myinput)
except ValueError:
throw ValueError(myinput + " is not a number")
doubleofmyinput=float(myinput)*2
print(doubleofmyinput)
</code></pre>