[英]Sort list of nested dictionaries by value
我有字典列表。 我需要對其進行排序。 如果這些字典中沒有嵌套字典,那就很好了。 但我需要對嵌套字典進行排序。
lis = [{"name": "Nandini", "age": {"name": "Nandini", "age": 20}},
{"name": "Manjeet", "age": 21},
{"name": "Nikhil", "age": 19}]
# using sorted and lambda to print list sorted
# by age
print("The list printed sorting by age: ")
print(sorted(lis, key=lambda i: i['age']))
所以,我有錯誤:
Traceback (most recent call last):
File "D:\json\111.py", line 8, in <module>
print(sorted(lis, key=lambda i: i['age']))
TypeError: '<' not supported between instances of 'int' and 'dict'
但是如果我替換那些嵌套的字典,它會很順利。 有一個答案 how to sort by subkey: sorting list of nested dictionaries in python但我需要一種如何按鍵排序的方法。
您可以將or
運算符與if/else
結合使用來指定鍵:
print(
sorted(
lis,
# Uses age if it is an integer else take the 'second level' age value
key=lambda i: i['age'] if isinstance(i['age'], int) else i['age']['age']
)
)
出去:
The list printed sorting by age:
[{'name': 'Nikhil', 'age': 19}, {'name': 'Nandini', 'age': {'name': 'Nandini', 'age': 20}}, {'name': 'Manjeet', 'age': 21}]
筆記:
如果您想在排序之前跳過所有具有嵌套“年齡”的項目,請過濾掉它們:
print(
sorted(
[item for item in lis if isinstance(item['age'], int)],
key=lambda i: i['age']
)
)
如果要處理任意數量的嵌套字典,可以使用遞歸 function 對值進行排序:
import sys
from pprint import pp
def getAge(d):
if isinstance(d, dict):
return getAge(d.get("age", None))
elif isinstance(d, int):
return d
else:
# An integer larger than any practical list or string index
return sys.maxsize
lis = [{"name": "Nandini", "age": {"name": "Nandini", "age": 20}},
{"name": "Manjeet", "age": 21},
{"name": "Valodja", "age": "NotANumber"},
{"name": "Nikhil", "age": 19}]
pp(sorted(lis, key=getAge))
Output:
[{'name': 'Nikhil', 'age': 19},
{'name': 'Nandini', 'age': {'name': 'Nandini', 'age': 20}},
{'name': 'Manjeet', 'age': 21},
{'name': 'Valodja', 'age': 'NotANumber'}]
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