[英]How to sort dictionary on first element of the key (tuple)
I have a dictionary where each key is a tuple of values, I want to use the sorted()
method to sort the dictionary on the very first element of my tuple. 我有一个字典,每个键都是一个值元组,我想使用
sorted()
方法对我的元组的第一个元素进行字典排序。 My code looks like this: 我的代码看起来像这样:
def mapData(header_list, dict_obj):
master_dict = {}
client_section_list = []
for element in header_list:
for row in dict_obj:
if (row['PEOPLE_ID'], row['DON_DATE']) == element:
client_section_list.append(row)
element = list(element)
element_list = [client_section_list[0]['DEDUCT_AMT'],
client_section_list[0]['ND_AMT'],
client_section_list[0]['DEDUCT_YTD'],
client_section_list[0]['NONDEDUCT_YTD']
]
try:
element_list.append((float(client_section_list[0]['DEDUCT_YTD']) +
float(client_section_list[0]['NONDEDUCT_YTD'])
))
except ValueError:
pass
element.extend(element_list)
element = tuple(element)
master_dict[element] = client_section_list
client_section_list = []
return sorted(master_dict, key=lambda key: key[master_dict[(1)]]
The last line is where I'm trying to find a way to sort it. 最后一行是我试图找到一种方法来排序它。 My tuple looks like this:
我的元组看起来像这样:
(312178078,6/22/15,25,0,25,0,25.0)
Not entirely sure what you are trying to do, particularly what that function is supposed to return. 不完全确定你要做什么,特别是那个函数应该返回什么。 I assume that you want to return the dictionary sorted by the first element in the key-tuples.
我假设您要返回按键元组中的第一个元素排序的字典。
For this, there are two things to note: 为此,有两点需要注意:
OrderedDict
instead OrderedDict
Some minimal example: 一些最小的例子:
>>> d = {(2,4): 1, (1,3): 2, (1,2): 3, (3,1): 4}
>>> sorted(d)
[(1, 2), (1, 3), (2, 4), (3, 1)]
>>> sorted(d.items())
[((1, 2), 3), ((1, 3), 2), ((2, 4), 1), ((3, 1), 4)]
>>> collections.OrderedDict(sorted(d.items()))
OrderedDict([((1, 2), 3), ((1, 3), 2), ((2, 4), 1), ((3, 1), 4)])
In your case, you probably want this: 在您的情况下,您可能想要这样:
return collections.OrderedDict(sorted(master_dict.items()))
As @tobias_k has mentioned, sorted
sorts tuples by its elements with decreasing priority, eg if you take a tuple (a, b, c)
the highest sorting priority goes to a
, then goes b
etc (by default sorted
uses object's comparison methods and this is how tuple
comparison works). 正如@tobias_k所提到的那样,
sorted
元素排序对元组sorted
排序,优先级降低,例如,如果你取一个元组(a, b, c)
,最高的排序优先级转到a
,然后转到b
等(默认sorted
使用对象的比较方法和这是tuple
比较的工作方式)。 So sorted(master_dict)
is all you need if you want a list of sorted keys, yet I believe you really want to leave the values 如果你想要一个排序键列表,那么你需要
sorted(master_dict)
,但我相信你真的想留下这些值
sorted(master_dict.items(), key=lambda key: key[0])
dict.items
returns tuples of form (key, value)
so here you need to specify the sorting key
. dict.items
返回表单(key, value)
元组,所以在这里你需要指定排序key
。
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