eval_python_有趣的模块_1

python eval()

eval(expression, globals=None, locals=None)
eval()方法解析expression, 并将值返回

参数

expression: 解析的表达式
globals: 字典格式
locals: 官方解释只要是map对象就行，我们一般使用字典
具体globals和loclas怎么用下方例子说明

返回

返回expression的值

例1：

x=1
print(eval("x + 1"))

输出
2

例2

# Perimeter of Square
def calculatePerimeter(l):
    return 4*l

# Area of Square
def calculateArea(l):
    return l*l


expression = input("Type a function: ")

for l in range(1, 5):
    if (expression == 'calculatePerimeter(l)'):
        print("If length is ", l, ", Perimeter = ", eval(expression))
    elif (expression == 'calculateArea(l)'):
        print("If length is ", l, ", Area = ", eval(expression))
    else:
        print('Wrong Function')
        break

输出：

 Type a function: calculateArea(l)
If length is  1 , Area =  1
If length