Removing duplicates in lists

Question

I want to write a program to check if a list has any duplicates and if it does it removes them and returns a new list with the items that weren't duplicated/removed. The code is as follows:

def remove_duplicates():
    t = ['a', 'b', 'c', 'd']
    t2 = ['a', 'c', 'd']
    for t in t2:
        t.append(t.remove())
    return t

Answer 1

To remove duplicates from List use, set as set does not contain duplicates and also is unordered.

For Example:

Example = ['a','b','c','d','a','a','b','c','d']

list(set(Example)) 

Output:

['b', 'd', 'c', 'a']

from collections import OrderedDict
OrderedDict((u, True) for u in Example).keys()

Output:

odict_keys(['a', 'b', 'c', 'd'])

Here, OrderedDict remembers the insertion order of keys, and does not change it when a value at a particular key is updated. We use True as one value was needed to unpack the list, which is shown below without using True.

from collections import OrderedDict
OrderedDict((u) for u in Example).keys()

Output

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-12-ce40dd697e48> in <module>
      1 from collections import OrderedDict
----> 2 OrderedDict((u) for u in Example).keys()

ValueError: need more than 1 value to unpack