Tukukkk

I have a for loop that returns a value or None depending on field being selected.

For Loop:

for fieldname, value in form.data.items():

    if value is not None:

        print(value)

Given below is the output of the print statement of the for loop:

store_name

None

store_location

None

I am trying to pass the output of the above loop statement to a function as shown below:

output = store_details() <<-- arguments to this function to only include non None items obtained from the above for loop statement

In the above example only store_name and store_location should be passes as arguments. How could I pass only the non None items as arguments? Please note the list arguments could vary each time hence I am trying to build this function such that the store_details function only passes non None values each time.

Update:

Given below is the loop I am trying to execute. This works fine if all the fields are selected (There are 5 fields in the page from which the user can select).

l = 

    for fieldname, value in form.data.items():

        if value is not None:

            l.append(value)

print(l)



p = l[:-1]



output = store_details(*p)

If any of the fields are not selected, it returns a 'None' which throws

psycopg2.ProgrammingError: column "none" does not exist in table

I would recommend you to use list-comprehension:

You can do either:

output = store_details([value for fieldname, value in form.data.items() if not value == None])

or (you can do form.data.values() to to retrieve only values of dictionary)

output = store_details([value for value in form.data.values() if not value == None])

And you can also store the value of list-comprehension and pass it:

l = [value for value in form.data.values() if not value == None]

output = store_details(l)

EDIT : The error is because None has been written as a string in value, not an object None therefore if clause not catching it.

>>> a= dict([('store_name', 'None'), ('store_type', 'store_type'), ('store_location', 'store_location'), ('csrf_token', 'ImI0MzQyYzcwZDk5NTVmMGQxMWY5YTk3NDhmNTNkNzJmMjQ5NWIzZTIi.Dtllqg.-SXYDYkBmQiPjSmo01VnDgSbZrE')])

>>> del a['csrf_token']

>>> a

{'store_name': 'None', 'store_type': 'store_type', 'store_location': 'store_location'}

>>> [i for i in a.values() if not i == 'None']

['store_type', 'store_location']

>>>

If you prefer of using your own code make this change:

l = 

a = form.data

del a['csrf_token'] # token field is removed



    for fieldname, value in a.items():

        if value is not 'None':

            l.append(value)

print(l)



output = store_details(*l)

You can do this in many ways actually. One is a dictionary comprehension:

fields = {field:value for field,value in form.data.items() if value != None and value != 'None' and field != 'csrf_token'}

output = store_details(**fields)

UPDATE
I've included the 'None' check and excluded the csrf_token. Please use and operator, not the or.