遍历列表并与嵌套字典进行比较。 避免 KeyError - Python

Question

I would like to do the following:

I got to the following code so far, but I'm stuck now how to ignore that Day from future actions performed in the loop.

If someone could help me that would be really appreciated!!

• Note that I cannot remove EU as a region, it needs to be taken into the logic even though the key is not in the nested dict.

Answer 1

error has to do with your

print("{} status is: ".format(region) + nested_status)

nested_status is NullType, but the print statement is expecting a string.

You could try something like this to avoid 'NonTypes'

dict.get(key[, default])
example
dict.get(key, -1)

check this snippet and modify your code accordingly

print(nested)
nested['SA'].pop('20200525')
print(nested)

Answer 2

Here is a working solution, check the updated answer at the bottom.

The reason you getting the "can not concatenate" Error is because "nested_status" is equal to "None" in some iterations and you tried to add a string to it ('...' + None) in the print statement. you should check if nested_status has a value first.

import datetime

dates = [datetime.datetime(2020, 7, 4, 0, 0), datetime.datetime(
    2020, 7, 6, 0, 0), datetime.datetime(2020, 7, 7, 0, 0)]

regions = ["SA", "CA", "EU"]

nested = {"SA": {"20200525": "H", "20201126": "C", "20201224": "H", "20200101": "C", "20201127": "C", "20200217": "C", "20200120": "C", "20200907": "C", "20200410": "C", "20200704": "C",
                 "20201225": "C"}, "CA": {"20200410": "C", "20200518": "C", "20200701": "C", "20200101": "C", "20201012": "C", "20201228": "C", "20201225": "C", "20200803": "C", "20200907": "C", "20200217": "C"}}

for region in regions:
    for d in dates:
        day = d.strftime("%Y%m%d")

        if (nested.get(region) or {}).get(day):
            print("Nested value found in {} ! {}".format(region, day))
        nested_status = (nested.get(region) or {}).get(day)
        if nested_status:
            if nested_status == 'C':
                continue                 #<-- skip this loop iteration if C
            print("{} status is: ".format(region) + nested_status)

if you are not interested "if nested_status == C" just skip the current date iteration.

if nested_status:
    if nested_status == 'C':
        continue                 #<-- skip this loop iteration if C
    print("{} status is: ".format(region) + nested_status)