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python-3.xlist-comprehensionnameerror

NameError: name 'd' is not defined in Python list comprehension

Trying to run the following code in python 3.7:

date_list = [datetime.datetime.strptime(d['date'], '%Y-%m-%d') for d in date_settings and d['date'] != None]

This is the resulting error, can someone please clarify to me why this list comprehension cant see its own variable?

date_list = [datetime.datetime.strptime(d['date'], '%Y-%m-%d') for d in date_settings and d['date'] != None]
NameError: name 'd' is not defined

here is the inputed array:

[{'date': '2020-05-08', 'changed_at': '2020-05-07T20:35:07.854Z'}, {'date': '2020-05-09', 'changed_at': '2020-05-07T20:35:40.604Z'}, {'date': '2020-05-10', 'changed_at': '2020-05-07T20:35:42.936Z'}]
Solution

  • Inside your comprehension, where you wrote

    for d in date_settings and d['date'] != None

    you should have if, not and.

    As you currently have it, the comprehension is trying to understand the expression

    date_settings and d['date'] != None

    as something that d should iterate through, which is why it doesn't know what d is supposed to mean here.