python 中是否有三元运算符

Question

I'm trying to do a ternary like operator for python to check if my dictionary value exist then use it or else leave it blank, for example in the code below I want to get the value of creator and assignee , if the value doesn't exist I want it to be '' if theres a way to use ternary operator in python?

Here's my code:

        in_progress_response = requests.request("GET", url, headers=headers, auth=auth).json()
        issue_list = []
        for issue in in_progress_response['issues'] :
            # return HttpResponse( json.dumps( issue['fields']['creator']['displayName'] ) )
            issue_list.append(
                            {
                                "id": issue['id'],
                                "key": issue['key'],
                                # DOESN'T WORK
                                "creator": issue['fields']['creator']['displayName'] ? '',
                                "is_creator_active": issue['fields']['creator']['active'] ? '',
                                "assignee": issue['fields']['assignee']['displayName'] ? '', 
                                "is_assignee_active": issue['fields']['assignee']['active'] ? '',
                                "updated": issue['fields']['updated'],
                            }
            )

         return issue_list

Answer 1

Ternary operators in python act as follows:

condition = True
foo = 3.14 if condition else 0

But for your particular use case, you should consider using dict.get() . The first argument specifies what you are trying to access, and the second argument specifies a default return value if the key does not exist in the dictionary.

some_dict = {'a' : 1}

foo = some_dict.get('a', '') # foo is 1
bar = some_dict.get('b', '') # bar is ''

Answer 2

You can use .get(…) [Django-doc] to try to fetch an item from a dictionary and return an optional default value in case the dictionary does not contain the given key, you thus can implement this as:

"creator": issue.get('fields', {}).get('creator', {}).get('displayName', ''),

the same with the other items.

Answer 3

if you want to use something like ternary then you can say

value = issue['fields']['creator']['displayName'] if issue['fields']['creator'] else ""