擅长:python、mysql、java
<p>不能在代码中使用<code>+</code>、<code>*</code>等,因为它们不是有效的标识符,但是可以使用<code>operator</code>模块和此处的字典来减少代码:</p>
<pre><code>from operator import mul,add,div,sub,pow,mod
dic = {'+':add, '-':sub, '*':mul, '**':pow, '%':mod, '/':div}
def calculator(n1,op,n2):
n1 = n1
n2 = n2
try:
return dic[op](n1,n2)
except KeyError:
return "Invalid Operator"
</code></pre>
<p>演示:</p>
<pre><code>>>> calculator(3,"**",3)
27
>>> calculator(3,"*",3)
9
>>> calculator(3,"+",3)
6
>>> calculator(3,"/",3)
1
>>> calculator(3,"&",3) # & is not defined in your dict
'Invalid Operator'
</code></pre>