Remove duplicate words from string python

Following example:

string1 = "calvin klein design dress calvin klein"

How can I remove the second two duplicates "calvin" and "klein"?

The result should look like

string2 = "calvin klein design dress"

only the second duplicates should be removed and the sequence of the words should not be changed!

Martin Thoma

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asked Oct 17, 2011 at 13:08

string1 = "calvin klein design dress calvin klein"
words = string1.split()
print (" ".join(sorted(set(words), key=words.index)))

This sorts the set of all the (unique) words in your string by the word's index in the original list of words.

answered Oct 17, 2011 at 13:40


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def unique_list(l):
    ulist = []
    [ulist.append(x) for x in l if x not in ulist]
    return ulist

a="calvin klein design dress calvin klein"
a=' '.join(unique_list(a.split()))

answered Oct 17, 2011 at 13:12


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In Python 2.7+, you could use collections.OrderedDict for this:

from collections import OrderedDict
s = "calvin klein design dress calvin klein"
print ' '.join(OrderedDict((w,w) for w in s.split()).keys())

answered Oct 17, 2011 at 13:21


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Cut and paste from the itertools recipes

from itertools import ifilterfalse

def unique_everseen(iterable, key=None):
    "List unique elements, preserving order. Remember all elements ever seen."
    # unique_everseen('AAAABBBCCDAABBB') --> A B C D
    # unique_everseen('ABBCcAD', str.lower) --> A B C D
    seen = set()
    seen_add = seen.add
    if key is None:
        for element in ifilterfalse(seen.__contains__, iterable):
            yield element
        for element in iterable:
            k = key(element)
            if k not in seen:
                yield element

I really wish they could go ahead and make a module out of those recipes soon. I'd very much like to be able to do from itertools_recipes import unique_everseen instead of using cut-and-paste every time I need something.

Use like this:

def unique_words(string, ignore_case=False):
    key = None
    if ignore_case:
        key = str.lower
    return " ".join(unique_everseen(string.split(), key=key))

string2 = unique_words(string1)

answered Oct 17, 2011 at 13:22


string2 = ' '.join(set(string1.split()))


.split() - it is a method to split string to list (without params it split by spaces)
set() - it is type of unordered collections that exclude dublicates
'separator'.join(list) - mean that you want to join list from params to string with 'separator' between elements

answered Nov 9, 2018 at 8:33

Remove duplicate words from string python


string = 'calvin klein design dress calvin klein'

def uniquify(string):
    output = []
    seen = set()
    for word in string.split():
        if word not in seen:
    return ' '.join(output)

print uniquify(string)

answered Oct 17, 2011 at 13:27

Remove duplicate words from string python


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You can use a set to keep track of already processed words.

words = set()
result = ''
for word in string1.split():
    if word not in words:
        result = result + word + ' '
print result

answered Oct 17, 2011 at 13:10

Pablo Santa CruzPablo Santa Cruz

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Several answers are pretty close to this but haven't quite ended up where I did:

def uniques( your_string ):    
    seen = set()
    return ' '.join( seen.add(i) or i for i in your_string.split() if i not in seen )

Of course, if you want it a tiny bit cleaner or faster, we can refactor a bit:

def uniques( your_string ):    
    words = your_string.split()

    seen = set()
    seen_add = seen.add

    def add(x):
        return x

    return ' '.join( add(i) for i in words if i not in seen )

I think the second version is about as performant as you can get in a small amount of code. (More code could be used to do all the work in a single scan across the input string but for most workloads, this should be sufficient.)

answered Oct 17, 2011 at 22:13

Chris PhillipsChris Phillips

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Use numpy function make an import its better to have an alias for the import (as np)

import numpy as np

and then you can bing it like this for removing duplicates from array you can use it this way

no_duplicates_array = np.unique(your_array)

for your case if you want result in string you can use

no_duplicates_string = ' '.join(np.unique(your_string.split()))

answered Jun 8, 2020 at 12:04

Sulman MalikSulman Malik

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11 and 2 work perfectly:

    s="the sky is blue very blue"
    slist = s.split()
    print " ".join(sorted(set(slist), key=slist.index))

and 2

    s="the sky is blue very blue"
    slist = s.split()
    print " ".join(sorted(set(slist), key=slist.index))

answered Apr 17, 2016 at 16:38


Question: Remove the duplicates in a string

 from _collections import OrderedDict

    a = "Gina Gini Gini Protijayi"

    aa = OrderedDict().fromkeys(a.split())
    print(' '.join(aa))
   # output => Gina Gini Protijayi

answered Jun 16, 2018 at 23:44

Remove duplicate words from string python

You can remove duplicate or repeated words from a text file or string using following codes -

from collections import Counter
for lines in all_words:

    new_data1=' '.join(lemmatize_sentence(line))
    new_data2 = word_tokenize(new_data1)

    # below code is for removal of repeated words

    for i in range(0, len(new_data3)):
        new_data3[i] = "".join(new_data3[i])
    UniqW = Counter(new_data3)
    new_data5 = " ".join(UniqW.keys())
    print (new_data5)


print (new_data)

P.S. -Do identations as per required. Hope this helps!!!

answered Jun 25, 2018 at 7:22

Remove duplicate words from string python

Without using the split function (will help in interviews)

def unique_words2(a):
    words = []
    spaces = ' '
    length = len(a)
    i = 0
    while i < length:
        if a[i] not in spaces:
            word_start = i
            while i < length and a[i] not in spaces:
                i += 1
        i += 1
    words_stack = []
    for val in words:  #
        if val not in words_stack:  # We can replace these three lines with this one -> [words_stack.append(val) for val in words if val not in words_stack]
            words_stack.append(val)  #
    print(' '.join(words_stack))  # or return, your choice

unique_words2('calvin klein design dress calvin klein') 


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answered Mar 6, 2020 at 12:06

initializing list

listA = [ 'xy-xy', 'pq-qr', 'xp-xp-xp', 'dd-ee']

print("Given list : ",listA)

using set() and split()

res = [set(sub.split('-')) for sub in listA]


print("List after duplicate removal :", res) 

Remove duplicate words from string python

Peter Csala

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answered Oct 17, 2021 at 12:39


You can do that simply by getting the set associated to the string, which is a mathematical object containing no repeated elements by definition. It suffices to join the words in the set back into a string:

def remove_duplicate_words(string):
        x = string.split()
        x = sorted(set(x), key = x.index)
        return ' '.join(x)

answered Nov 9, 2018 at 8:28


How do I remove duplicates from a string in Python?

1) Sort the elements. 2) Now in a loop, remove duplicates by comparing the current character with previous character. 3) Remove extra characters at the end of the resultant string.

How do I remove repetitive words from a string?

Define a string..
Convert the string into lowercase to make the comparison insensitive..
Split the string into words..
Two loops will be used to find duplicate words. ... .
If a match found, then increment the count by 1 and set the duplicates of word to '0' to avoid counting it again..

How do you remove duplicates from a comma separated string in Python?

We can do this with the SPLIT function. This function returns a row of cells divided based on the delimiter. To remove duplicate values, we have to use the UNIQUE function. Since the UNIQUE function works for cells in different rows, we'll have to transpose our SPLIT output using the TRANSPOSE function.

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