Question

我正在尝试创建一个非常简单的Python程序，我可以通过其名称输入一个行星并且具有所述的近似距离。目前，我列出了七个行星，等于它们在该评估函数正下方的距离。

这就是代码目前的样子：

def = def Planet_Calculations():
    Planet = exec(input("What planet are you trying to calculate the distance for? (Note: Pluto is no longer a planet!) "))
    Mercury = 56,974,146
    Venus = 25,724,767 
    Earth = 0 
    Mars = 48,678,219
    Jupiter = 390,674,710
    Saturn = 792,248,270
    Uranus = 1,692,662,530
    Neptune = 2,703,959,960

print("The distance to the specified planet is approxametly:" , Planet, "million miles from Earth." )

Planet_Calculations()

当我尝试输入诸如＆＃34; Mars＆＃34;进入eval，我不知道如何让程序输入其进一步向下打印功能的距离。我非常感谢任何类型的反馈或帮助。

Answer 1

使用dict映射行星到元组::

def planet_calculations():
    planet = input("What planet are you trying to calculate the distance for? (Note: Pluto is no longer a planet!) ")
    planets = {'Mercury': (56, 974, 146), 'Neptune': (2, 703, 959, 960), 'Jupiter': (390, 674, 710),
               'Uranus': (1, 692, 662, 530),
               'Mars': (48, 678, 219), 'Earth': 0, 'Venus': (25, 724, 767), 'Saturn': (792, 248, 270)}
    print("The distance to the specified planet is approxametly: {} million miles from Earth."
          .format(planets[planet])

如果您希望像"56,974,146"这样的输出将值存储为字符串而不是元组。

此外，如果您想使用函数外部的值，则需要将其返回：

def planet_calculations():
    planet = input("What planet are you trying to calculate the distance for? (Note: Pluto is no longer a planet!) ")
    planets = {'Mercury': (56, 974, 146), 'Neptune': (2, 703, 959, 960), 'Jupiter': (390, 674, 710),
               'Uranus': (1, 692, 662, 530),
               'Mars': (48, 678, 219), 'Earth': 0, 'Venus': (25, 724, 767), 'Saturn': (792, 248, 270)}
    return planets[planet]
print("The distance to the specified planet is approxametly: {} million miles from Earth."
        .format(planet_calculations()))

Python：如何在使用eval函数时调用变量？

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