python如何让减价乘除变成变量之后再变回来

Question

a = 1
b = 2
for opt in ["+", "-", "*", "/"]:
    print(aoptb)

如上图所示，当然我的语法是错误的，我想最后输出 3，-1，2，0.5 ，正确的语法应该如何去写

Answer 1

a = 1
b = 2
for opt in ["+", "-", "*", "/"]:
    print(eval(str(a) + opt + str(b)))

Answer 2

python3

>>> import operator as opt
>>> optr={'加':opt.add,'减':opt.sub,'乘':opt.mul,'除':opt.truediv}
>>> a,b=1,2
>>> for k,o in optr.items():
    print('%s: %s'%(k,o(a,b)))

    
乘: 2
加: 3
除: 0.5
减: -1

Answer 3

def add(a, b):
    return a + b
def minus(a, b):
    return a - b
def multiply(a, b):
    return a * b
def divide(a, b):
    return float(a) / b

ops = [add, minus, multiply, divide]
for op in ops:
    print op(1, 2)