如何按照定义的顺序遍历Python字典? [英] How to iterate over a Python dictionary in defined order?

问题描述

我试图遍历以特定顺序定义的字典，但是它总是以与我在代码中定义的顺序不同的顺序进行迭代.这只是我要尝试做的一个基本示例.我要遍历的字典更大，具有更复杂的命名键，并且不是字母/数字顺序.

I'm trying to iterate over a dictionary that I have defined in a specific order, but it always iterates in a different order than what I have defined in my code. This is just a basic example of what I'm trying to do. The dictionary I'm iterating over is much larger, has much more complexly named keys, and is not in alphabetical/numerical order.

level_lookup = \
{
'PRIORITY_1' :   { 'level' : 'BAD',   'value' :   ''  },
'PRIORITY_2' :   { 'level' : 'BAD',   'value' :   ''  },
'PRIORITY_3' :   { 'level' : 'BAD',   'value' :   ''  },
'PRIORITY_4' :   { 'level' : 'BAD',   'value' :   ''  },
'PRIORITY_5' :   { 'level' : 'CHECK', 'value' :   ''  },
'PRIORITY_6' :   { 'level' : 'CHECK', 'value' :   ''  },
'PRIORITY_7' :   { 'level' : 'GOOD',  'value' :   ''  },
'PRIORITY_8' :   { 'level' : 'GOOD',  'value' :   ''  },
}

for priority in level_lookup:
    if( level_lookup[ priority ][ 'value' ] == 'TRUE' ):
        set_levels += str( priority ) + '\n'

我需要在迭代过程中保留字典的顺序.我的订单不是按字母顺序排列的，因此按字母顺序进行排序实际上并没有帮助.有什么办法吗?我已经尝试过`level_lookup.items()，但这也不能维持我的订单.

I need the order that I define the dictionary in to be preserved during iteration. My order is not alphabetical, so sorting alphabetically wouldn't really help. Is there any way to do this? I've tried `level_lookup.items(), but that doesn't maintain my order either.

推荐答案

您应该使用 OrderedDict .它完全按照您想要的方式工作，但是您需要以这种方式进行定义.另外，您可以按顺序列出一个键列表，然后遍历该列表并访问字典.类似于以下内容:

You should use an OrderedDict. It works exactly the way you want it, however you need to define it that way. Alternatively, you can have a list of keys in order, and iterate through the list and access the dictionary. Something along the lines of:

level_lookup_order = ['PRIORITY_1', 'PRIORITY_2', ...]
for key in level_lookup_order:
    if key in level_lookup:
        do_stuff(level_lookup[key])

但是，这很难维护，因此我建议您只使用OrderedDict.

This will be a pain to maintain, though, so I recommend you just use the OrderedDict.

最后一个选择是，您可以使用常量".喜欢，

As a last option, you could use 'constants'. Like,

PRIORITY_1 = 1
PRIORITY_2 = 2
...
lookup_order = {PRIORITY_1: 42, PRIORITY_2: 24, ...}

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