python如何创建可互换值列表?

问题描述

我正在处理Midi音符，midi编号和频率.我应该使用python中的哪种列表来引用任何一个属性并获取其他属性?

I'm working with midi note, midi number, and frequency. What kind of list in python should I use to refer to any one attribute and get the other attributes?

例如:

• 输入:"C3"，返回frequency并获得261.6255653006.

输入:261.6255653006，返回midinumber并获得60

输入:60，返回midinote并获得"C3"

我将使用什么语法，函数，对象或列表类型?

what syntax, functions, objects, or list type would I use?

推荐答案

就像我在评论中说的那样，您可能正在寻找元组字典.示例:

Like I said in the comments, a dictionary of tuples is what you're probably looking for. Example:

data = {'C3': ('frequency', 261.6255653006), 
    261.6255653006: ('midinumber', 60), 
    60: ('midinote', 'C3'),
}

要验证您的输入，您可以执行以下操作:

To validate your input you can do:

input = raw_input()
try:
    key = float(input)
except ValueError:
    key = input

try:
    value = data[key]
except KeyError:
    print "Invalid input. Valid keys are: " + ', '.join(data.keys())
else:
    #input was valid, so value == data[key]

对索引进行索引就像对列表进行索引一样.但是，它们是不可变的，这意味着您无法更改它们或将新项目添加到它们.我相信您的情况就是如此.

Tuples are indexed just like lists are. However, they are immutable which means you can't change them or append new items to them. And I believe that's desired in your case.

字典通过键索引，例如data['C3']返回('frequency', 261.6255653006)，而data['C3'][0]返回'frequency'.

Dictionaries are indexed by keys, for example data['C3'] returns ('frequency', 261.6255653006) and data['C3'][0] returns 'frequency'.

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