# Remove all duplicates from a given string in Python

We are given a string and we need to remove all duplicates from it? What will be the output if the order of character matters? Examples:

Input : geeksforgeeks
Output : geksfor

This problem has an existing solution please refer to Remove all duplicates from a given string

Method 1:

## Python3

 `from` `collections ``import` `OrderedDict `   `# Function to remove all duplicates from string ` `# and order does not matter ` `def` `removeDupWithoutOrder(``str``): `   `    ``# set() --> A Set is an unordered collection ` `    ``#         data type that is iterable, mutable, ` `    ``#         and has no duplicate elements. ` `    ``# "".join() --> It joins two adjacent elements in ` `    ``#             iterable with any symbol defined in ` `    ``#             "" ( double quotes ) and returns a ` `    ``#             single string ` `    ``return` `"".join(``set``(``str``)) `   `# Function to remove all duplicates from string ` `# and keep the order of characters same ` `def` `removeDupWithOrder(``str``): ` `    ``return` `"".join(OrderedDict.fromkeys(``str``)) `   `# Driver program ` `if` `__name__ ``=``=` `"__main__"``: ` `    ``str` `=` `"geeksforgeeks"` `    ``print` `(``"Without Order = "``,removeDupWithoutOrder(``str``)) ` `    ``print` `(``"With Order = "``,removeDupWithOrder(``str``)) `

Output

```Without Order =  foskerg
With Order =  geksfor```

Time complexity: O(n)
Auxiliary Space: O(n)

Method 2:

## Python3

 `def` `removeDuplicate(``str``): ` `    ``s``=``set``(``str``) ` `    ``s``=``"".join(s) ` `    ``print``(``"Without Order:"``,s) ` `    ``t``=``"" ` `    ``for` `i ``in` `str``: ` `        ``if``(i ``in` `t): ` `            ``pass` `        ``else``: ` `            ``t``=``t``+``i ` `        ``print``(``"With Order:"``,t) ` `    `  `str``=``"geeksforgeeks"` `removeDuplicate(``str``) `

Output

```Without Order: kogerfs
With Order: g
With Order: ge
With Order: ge
With Order: gek
With Order: geks
With Order: geksf
With Order: geksfo
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor```

Time complexity: O(n)
Auxiliary Space: O(n)

What do OrderedDict and fromkeys() do?

An OrderedDict is a dictionary that remembers the order of the keys that were inserted first. If a new entry overwrites an existing entry, the original insertion position is left unchanged.

For example, see below code snippet :

## Python3

 `from` `collections ``import` `OrderedDict `   `ordinary_dictionary ``=` `{} ` `ordinary_dictionary[``'a'``] ``=` `1` `ordinary_dictionary[``'b'``] ``=` `2` `ordinary_dictionary[``'c'``] ``=` `3` `ordinary_dictionary[``'d'``] ``=` `4` `ordinary_dictionary[``'e'``] ``=` `5`   `# Output = {'a': 1, 'c': 3, 'b': 2, 'e': 5, 'd': 4} ` `print` `(ordinary_dictionary)     `   `ordered_dictionary ``=` `OrderedDict() ` `ordered_dictionary[``'a'``] ``=` `1` `ordered_dictionary[``'b'``] ``=` `2` `ordered_dictionary[``'c'``] ``=` `3` `ordered_dictionary[``'d'``] ``=` `4` `ordered_dictionary[``'e'``] ``=` `5`   `# Output = {'a':1,'b':2,'c':3,'d':4,'e':5} ` `print` `(ordered_dictionary)     `

Output

```{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)])```

Time complexity: O(n)
Auxiliary Space: O(1)

fromkeys() creates a new dictionary with keys from seq and values set to a value and returns a list of keys, fromkeys(seq[, value]) is the syntax for fromkeys() method. Parameters :

• seq : This is the list of values that would be used for dictionary keys preparation.
• value : This is optional, if provided then the value would be set to this value.

For example, see below code snippet :

## Python3

 `from` `collections ``import` `OrderedDict` `seq ``=` `(``'name'``, ``'age'``, ``'gender'``)` `dict` `=` `OrderedDict.fromkeys(seq)`   `# Output = {'age': None, 'name': None, 'gender': None}` `print` `(``str``(``dict``)) ` `dict` `=` `OrderedDict.fromkeys(seq, ``10``)`   `# Output = {'age': 10, 'name': 10, 'gender': 10}` `print` `(``str``(``dict``))       `

Output

```OrderedDict([('name', None), ('age', None), ('gender', None)])
OrderedDict([('name', 10), ('age', 10), ('gender', 10)])```

Time complexity: O(n)
Auxiliary Space: O(1)

If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Method 5:  using operator.countOf() method

## Python3

 `import` `operator as op`     `def` `removeDuplicate(``str``):` `    ``s ``=` `set``(``str``)` `    ``s ``=` `"".join(s)` `    ``print``(``"Without Order:"``, s)` `    ``t ``=` `""` `    ``for` `i ``in` `str``:` `        ``if` `op.countOf(t, i) > ``0``:` `            ``pass` `        ``else``:` `            ``t ``=` `t``+``i` `        ``print``(``"With Order:"``, t)`     `str` `=` `"geeksforgeeks"` `removeDuplicate(``str``)`

Output

```Without Order: goksefr
With Order: g
With Order: ge
With Order: ge
With Order: gek
With Order: geks
With Order: geksf
With Order: geksfo
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor
With Order: geksfor```

Time Complexity: O(N)

Auxiliary Space : O(N)

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