Is there a way to sort and remove duplicates from a list in an easier way?

Question

I am trying to remove the duplicates from a list. First tried to do so by comparing the elements of 2 lists but i am no satisfied with this method. Is there an easier way?

list1 = [a, b, b, c, c, d,]
list2 = [b, c]
for list1 in list2:
   list.append(list.remove())
return list

But this way i remove all of the members that are in list1 and list2 and i want to remove only the duplicates.

Please give us input in correct format. Are `a`, `b`,.. python variables or string literals? — Austin, Apr 25 '19 at 13:30
What does list2 have to do with removing duplicates from list1? Also, does removing duplicates mean `[a,d]` or `[a,b,c,d]`? — chepner, Apr 25 '19 at 13:32

score 0 · Accepted Answer · edited Apr 25 '19 at 13:45

0

You can try this

readmelist.sort()
readmelist = list(dict.fromkeys(readmelist))

edited Apr 25 '19 at 13:45

char

2,063
3
15
26

answered Apr 25 '19 at 13:33

codingdiet

43
2

score 0 · Answer 2 · answered Apr 25 '19 at 13:35

0

This will generate a new list called 'list' that contains no duplicat items. Also note that you have an extra , at the end of list1 which will cause errors and that a is read as a variable, to read it as a string use 'a'.

list1 = ['a', 'b', 'b', 'c', 'c', 'd']
list2 = ['b', 'c']
list = []
for i in list1:
    if i not in list2:
        list.append(i)
print(list)

answered Apr 25 '19 at 13:35

BillyN

185
2
10

The extra comma at the end of the OPs list is perfectly valid. – brunns Apr 25 '19 at 13:37

Arbor Chaos · Answer 3 · 2019-04-25T13:46:21.137

to the issue removing duplicates:

list1=list(set(list1))

But I honestly don't know what you want with your second list. If you want to remove all items which are in the second list from list one use a for loop. If you want to remove all items which are in the second list and several times in the first one, you should use a for loop with a counter and only remove the entry if counter >=1. For the last case even better would be using a mask and then remove the values (you do not have to loop over your list over and over this way).

Maybe you want something like

list_out= list( set(list1) - set(list2))

EDIT: just saw this is a duplicate question from here and therefore should be closed.

score 0 · Answer 4 · answered Apr 25 '19 at 13:53

Easiest way that I have found so far is using dictionary.

list1 = [a, b, b, c, c, d,] list1 = list(dict.fromkeys(list1))

dict.fromkeys(object) creates a dictionary with keys but no values.

Since a dictionary can only have unique keys, duplicates are automatically removed.

We then cast the dictionary into a list using list('Dictionary_Here')

Hope this helps.

Is there a way to sort and remove duplicates from a list in an easier way?

4 Answers4