Removing duplicate strings from a list in python [duplicate]

Question

If I have a string list ,

a = ["asd","def","ase","dfg","asd","def","dfg"]

how can I remove the duplicates from the list?

Check this answer if you want to preserve order: stackoverflow.com/a/53657523/3107708 — Johann
– Johann, Commented Dec 8, 2023 at 15:35

Mark Byers · Accepted Answer · 2011-11-20 08:32:56Z

107

Convert to a set:

a = set(a)

Or optionally back to a list:

a = list(set(a))

Note that this doesn't preserve order. If you want to preserve order:

seen = set()
result = []
for item in a:
    if item not in seen:
        seen.add(item)
        result.append(item)

See it working online: ideone

answered Nov 20, 2011 at 8:32

Mark Byers

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Comments

Krumelur · Accepted Answer · 2011-11-20 08:32:43Z

17

Use the set type to remove duplicates

a = list(set(a))

answered Nov 20, 2011 at 8:32

Krumelur

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Comments

rossipedia · Accepted Answer · 2011-11-20 08:33:03Z

6

You could pop 'em into a set and then back into a list:

a = [ ... ]
s = set(a)
a2 = list(s)

answered Nov 20, 2011 at 8:33

rossipedia

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Comments

murasing · Accepted Answer · 2014-02-07 09:59:49Z

6

def getUniqueItems(iterable):
result = []
for item in iterable:
    if item not in result:
        result.append(item)
return result

print (''.join(getUniqueItems(list('apple'))))

P.S. Same thing like one of the answers here but a little change, set is not really required !

edited Feb 7, 2014 at 9:59

answered Feb 7, 2014 at 9:49

murasing

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2 Comments

tumultous_rooster Over a year ago

does this code snippet preserve the order?

ReneSac Over a year ago

It does preserve order, but has quadratic complexity, and that is bad for any list remotely big.

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