How a search one list and see if all those items are in second list and then print (if any) all the missing elements and how many there are?

Question

I am currently learning python. I would like to know how can I compare two list. I have two lists:

days = ['sunday', 'monday', 'tuesday', 'wednesday', 'friday']
new_days = ['weekend', 'wednesday', 'saturday', 'sunday', 'monday','thursday']

How can I write, I'm assuming a loop, a code to see if all the elements from the days list are in the new_days list and then if there are any missing elements from the days list that aren't in the new_days list print out how many are missing and print out the ones that are missing? Would I use the all() function to compare the two to begin with?

I have used the set() but it seems like that just does a Union. — Abdul-Aziz Muhammad, Apr 09 '19 at 21:52
Possible duplicate of [How can I compare two lists in python and return matches](https://stackoverflow.com/questions/1388818/how-can-i-compare-two-lists-in-python-and-return-matches) — vurmux, Apr 09 '19 at 21:52
Saying "I used set()" doesn't really tell us much. _How_ did you use it? Show us the code, and explain how those results aren't what you wanted. — John Gordon, Apr 09 '19 at 21:54
No it is not a duplicate. I did the set(): @vurmux (set(days) - set(new_days) — Abdul-Aziz Muhammad, Apr 10 '19 at 17:18

score 0 · Accepted Answer · answered Apr 09 '19 at 21:47

0

if you are just interested in finding the difference between both list you could use the following code:

days = ['sunday', 'monday', 'tuesday', 'wednesday', 'friday']
new_days = ['weekend', 'wednesday', 'saturday', 'sunday', 'monday','thursday']
difference = list(set(days) - set(new_days))

how this helps

answered Apr 09 '19 at 21:47

Nazim Kerimbekov

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This was very helpful! So using the set for both lists and then converting them into list to find the different. Thank you so much! But how can I loop this to check each item and then when finishing checking all items print? – Abdul-Aziz Muhammad Apr 09 '19 at 21:54
@Abdul-AzizMuhammad I'm happy that this helped! if you could click on the grey tick near the answer to validate it that would be great! – Nazim Kerimbekov Apr 09 '19 at 21:56
My only question is why use list if they are already in list format? – Abdul-Aziz Muhammad Apr 10 '19 at 17:23
We use list because we have convert both variables into sets using set(). In order to get the final result as a list we have to use list(). – Nazim Kerimbekov Apr 10 '19 at 17:24

How a search one list and see if all those items are in second list and then print (if any) all the missing elements and how many there are?

1 Answers1