如何添加字典的特定元素

Question

sleeps=[{"summaryId ": "x209bf59-59b0c5a8-585c ", 
         "validation ": "AUTO_TENTATIVE ", 
         "durationInSeconds ": 22620, 
         "startTimeInSeconds ": 1504757160, 
         "awakeDurationInSeconds ": 900, 
         "startTimeOffsetInSeconds ": -14400, 
         "deepSleepDurationInSeconds ": 8160, 
         "lightSleepDurationInSeconds ": 13560},
        {"summaryId ": "x209bf59-59b0c5a8-23a0 ", 
         "validation ": "AUTO_TENTATIVE ",
         "durationInSeconds ": 9120, 
         "startTimeInSeconds ": 1504757160,
         "awakeDurationInSeconds ": 300, 
         "startTimeOffsetInSeconds ": -14400, 
         "deepSleepDurationInSeconds ": 1680, 
         "lightSleepDurationInSeconds ": 7140}
       ]

res = sum([x["durationInSeconds"] for x in sleeps]) 
print(res)

这是抛出 Keyerror.

Answer 1

您要修改的键在您的字典定义中有冗余space

"durationInSeconds "
                  ^

Answer 2

散列和比较会考虑空格。如果它们并排打印，可能更容易发现差异：

"durationInSeconds "
"durationInSeconds"

第一个有尾随空格。

>>> hash(s1) == hash(s2)
False
>>> s1 == s2
False

所以它们在任何方面都不相等，这也解释了 KeyError。要修复它，您需要删除字典中的尾随空格，或者使用尾随空格查找键。例如：

>>> res = sum([x["durationInSeconds "] for x in sleeps]) 
>>> print(res)
31740

如何添加字典的特定元素

How to add particular element of dict

python

dictionary

keyerror

python-3.6