我有一本嵌套的字典。是否只有一种方法可以安全地传递价值观?
try:
example_dict['key1']['key2']
except KeyError:
pass
或者python有一个类似get()的方法用于嵌套字典?
当前回答
def safeget(_dct, *_keys):
if not isinstance(_dct, dict): raise TypeError("Is not instance of dict")
def foo(dct, *keys):
if len(keys) == 0: return dct
elif not isinstance(_dct, dict): return None
else: return foo(dct.get(keys[0], None), *keys[1:])
return foo(_dct, *_keys)
assert safeget(dict()) == dict()
assert safeget(dict(), "test") == None
assert safeget(dict([["a", 1],["b", 2]]),"a", "d") == None
assert safeget(dict([["a", 1],["b", 2]]),"a") == 1
assert safeget({"a":{"b":{"c": 2}},"d":1}, "a", "b")["c"] == 2
其他回答
递归法(мб п п и и одитс)
示例dict类型:
foo = [{'feature_name': 'Sample Creator > Contract Details > Elements of the page',
'scenarios': [{'scenario_name': 'SC, CD, Elements of the page',
'scenario_status': 'failed',
'scenario_tags': None,
'steps': [{'duration': 0,
'name': 'I open application Stage and login by '
'SPT_LOGIN and password SPT_PWD',
'status': 'untested'},
{'duration': 0,
'name': 'I open Sample Creator query page',
'status': 'untested'},
{'duration': 7.78166389465332,
'name': 'I open application Stage and login by '
'SPT_LOGIN and password SPT_PWD',
'status': 'passed'},
{'duration': 3.985326051712036,
'name': 'I open Sample Creator query page',
'status': 'passed'},
{'duration': 2.9063704013824463,
'name': 'Enter value: '
'X-2008-CON-007,X-2011-CON-016 in '
'textarea: project_text_area sleep: 1',
'status': 'passed'},
{'duration': 4.4447715282440186,
'name': 'I press on GET DATA',
'status': 'passed'},
{'duration': 1.1209557056427002,
'name': 'Verify the top table on Contract Details',
'status': 'passed'},
{'duration': 3.8173601627349854,
'name': 'I export contract_details table by offset '
'x:100, y:150',
'status': 'passed'},
{'duration': 1.032956600189209,
'name': 'Check data of '
'sc__cd_elements_of_the_page_1 and skip '
'cols None',
'status': 'passed'},
{'duration': 0.04593634605407715,
'name': "Verify 'Number of Substances' column "
'values',
'status': 'passed'},
{'duration': 0.10199904441833496,
'name': 'Substance Sample Details bottom table '
'columns',
'status': 'passed'},
{'duration': 0.0009999275207519531,
'name': 'Verify the Substance Sample Details '
'bottom table',
'status': 'passed'},
{'duration': 3.8558616638183594,
'name': 'I export substance_sample_details table '
'by offset x:100, y:150',
'status': 'passed'},
{'duration': 1.0329277515411377,
'name': 'Check data of '
'sc__cd_elements_of_the_page_2 and skip '
'cols None',
'status': 'passed'},
{'duration': 0.2879970073699951,
'name': 'Click on AG-13369',
'status': 'passed'},
{'duration': 3.800830364227295,
'name': 'I export substance_sample_details table '
'by offset x:100, y:150',
'status': 'passed'},
{'duration': 1.0169551372528076,
'name': 'Check data of '
'sc__cd_elements_of_the_page_3 and skip '
'cols None',
'status': 'passed'},
{'duration': 1.7484464645385742,
'name': 'Select all cells, table: 2',
'status': 'passed'},
{'duration': 3.812828779220581,
'name': 'I export substance_sample_details table '
'by offset x:100, y:150',
'status': 'passed'},
{'duration': 1.0029594898223877,
'name': 'Check data of '
'sc__cd_elements_of_the_page_2 and skip '
'cols None',
'status': 'passed'},
{'duration': 1.6729373931884766,
'name': 'Set window size x:800, y:600',
'status': 'passed'},
{'duration': 30.145705699920654,
'name': 'All scrollers are placed on top 6 and far '
'left 8',
'status': 'failed'}]}]},
{'feature_name': 'Sample Creator > Substance Sample History > Elements of the '
'page',
'scenarios': [{'scenario_name': 'SC, SSH, Elements of the page',
'scenario_status': 'passed',
'scenario_tags': None,
'steps': [{'duration': 0,
'name': 'I open application Stage and login by '
'SPT_LOGIN and password SPT_PWD',
'status': 'untested'},
{'duration': 0,
'name': 'I open Sample Creator query page',
'status': 'untested'},
{'duration': 7.305850505828857,
'name': 'I open application Stage and login by '
'SPT_LOGIN and password SPT_PWD',
'status': 'passed'},
{'duration': 3.500955104827881,
'name': 'I open Sample Creator query page',
'status': 'passed'},
{'duration': 3.0419492721557617,
'name': 'Enter value: NOA401800 SYN-NOA '
'A,S4A482070C SYN-ISN-OLD '
'O,S04A482167T,S04A482190Y,CSAA796564,CSCD106701 '
'in textarea: id_text_area sleep: 1',
'status': 'passed'},
{'duration': 49.567158460617065,
'name': 'I press on GET DATA',
'status': 'passed'},
{'duration': 0.13904356956481934,
'name': 'Open substance_sample_history',
'status': 'passed'},
{'duration': 1.1039845943450928,
'name': 'Columns displayed',
'status': 'passed'},
{'duration': 3.881945848464966,
'name': 'I export export_parent_table table by '
'offset x:100, y:150',
'status': 'passed'},
{'duration': 1.0334820747375488,
'name': 'Check data of '
'sc__ssh_elements_of_the_page_1 and skip '
'cols None',
'status': 'passed'},
{'duration': 0.0319981575012207,
'name': "Title is 'Additional Details for Marked "
"Rows'",
'status': 'passed'},
{'duration': 0.08897256851196289,
'name': 'Columns displayed (the same as in top '
'table)',
'status': 'passed'},
{'duration': 25.192569971084595,
'name': 'Verify the content of the bottom table',
'status': 'passed'},
{'duration': 4.308935880661011,
'name': 'I export '
'additional_details_for_marked_rows table '
'by offset x:100, y:150',
'status': 'passed'},
{'duration': 1.0089836120605469,
'name': 'Check data of '
'sc__ssh_elements_of_the_page_1 and skip '
'cols None',
'status': 'passed'}]}]}]
代码:
def get_keys(_dict: dict, prefix: list):
prefix += list(_dict.keys())
return prefix
def _loop_elements(elems:list, prefix=None, limit=None):
prefix = prefix or []
limit = limit or 9
try:
if len(elems) != 0 and isinstance(elems, list):
for _ in elems:
if isinstance(_, dict):
get_keys(_, prefix)
for item in _.values():
_loop_elements(item, prefix, limit)
return prefix[:limit]
except TypeError:
return
>>>goo = _loop_elements(foo,limit=9)
>>>goo
['feature_name', 'scenarios', 'scenario_name', 'scenario_status', 'scenario_tags', 'steps', 'duration', 'name', 'status']
unutbu回答的一个改编，我发现在我自己的代码中很有用:
example_dict.setdefaut('key1', {}).get('key2')
如果key1还没有这个键，它会为它生成一个字典条目，以避免出现KeyError。如果您希望像我这样以包含键对的嵌套字典结束，这似乎是最简单的解决方案。
我稍微改变了一下答案。我添加了检查，如果我们使用列表与数字。 所以现在我们可以用任何一种方法。deep_get(allTemp，[0]，{})或deep_get(getMinimalTemp， [0, minimalTemperatureKey]， 26)等
def deep_get(_dict, keys, default=None):
def _reducer(d, key):
if isinstance(d, dict):
return d.get(key, default)
if isinstance(d, list):
return d[key] if len(d) > 0 else default
return default
return reduce(_reducer, keys, _dict)
通过把所有这些答案和我做的小改变结合起来，我认为这个函数会很有用。安全、快捷、易于维护。
def deep_get(dictionary, keys, default=None):
return reduce(lambda d, key: d.get(key, default) if isinstance(d, dict) else default, keys.split("."), dictionary)
例子:
from functools import reduce
def deep_get(dictionary, keys, default=None):
return reduce(lambda d, key: d.get(key, default) if isinstance(d, dict) else default, keys.split("."), dictionary)
person = {'person':{'name':{'first':'John'}}}
print(deep_get(person, "person.name.first")) # John
print(deep_get(person, "person.name.lastname")) # None
print(deep_get(person, "person.name.lastname", default="No lastname")) # No lastname
如果您想使用另一个库来解决问题，这是最好的方法
https://github.com/maztohir/dict-path
from dict-path import DictPath
data_dict = {
"foo1": "bar1",
"foo2": "bar2",
"foo3": {
"foo4": "bar4",
"foo5": {
"foo6": "bar6",
"foo7": "bar7",
},
}
}
data_dict_path = DictPath(data_dict)
data_dict_path.get('key1/key2/key3')
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