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# Python – Dictionaries with Unique Value Lists

Given List of dictionaries with list values, extract unique dictionaries.

Input : [{‘Gfg’: [2, 3], ‘is’ : [7, 8], ‘best’ : }, {‘Gfg’: [2, 3], ‘is’ : [7, 8], ‘best’ : }]
Output : [{‘Gfg’: [2, 3], ‘is’: [7, 8], ‘best’: }]
Explanation : Both are similar dictionaries, and hence 1 is removed.

Input : [{‘Gfg’: [2, 3], ‘is’ : [7, 8], ‘best’ : }, {‘Gfg’: [2, 3], ‘is’ : [7, 8], ‘best’ : [10, 11]}]
Output : [{‘Gfg’: [2, 3], ‘is’: [7, 8], ‘best’: }, {‘Gfg’: [2, 3], ‘is’: [7, 8], ‘best’: [10, 11]}]
Explanation : None duplicate.

Method #1 : Using loop

This is one of the ways in which this task can be performed. In this, we iterate for each dictionary and memoize it, and prevent it from adding to result.

## Python3

 `# Python3 code to demonstrate working of``# Unique Value Lists Dictionaries``# Using loop` `# initializing lists``test_list ``=` `[{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``, ``8``], ``'best'` `: [``10``]},``             ``{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``], ``'best'` `: [``10``]},``             ``{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``, ``8``], ``'best'` `: [``10``]}]` `# printing original list``print``(``"The original list : "` `+` `str``(test_list))` `# Using loop to iterate through elements``# result array to also keep track of already occurred elements``res ``=` `[]``for` `sub ``in` `test_list:``    ``if` `sub ``not` `in` `res:``        ``res.append(sub)` `# printing result``print``(``"List after duplicates removal : "` `+` `str``(res))`

Output

```The original list : [{'Gfg': [2, 3], 'is': [7, 8], 'best': }, {'Gfg': [2, 3], 'is': , 'best': }, {'Gfg': [2, 3], 'is': [7, 8], 'best': }]
List after duplicates removal : [{'Gfg': [2, 3], 'is': [7, 8], 'best': }, {'Gfg': [2, 3], 'is': , 'best': }]```

Time complexity: O(n), where n is the length of the test_list. The  loop takes O(n) time
Auxiliary Space: O(n), extra space of size n is required

Method #2 : Using list comprehension

This is yet another way in which this task can be performed. In this, similar approach is employed as above, just the difference of encapsulating result in list comprehension for one-liner.

## Python3

 `# Python3 code to demonstrate working of``# Unique Value Lists Dictionaries``# Using list comprehension` `# initializing lists``test_list ``=` `[{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``, ``8``], ``'best'` `: [``10``]},``             ``{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``], ``'best'` `: [``10``]},``             ``{``'Gfg'``:  [``2``, ``3``], ``'is'` `: [``7``, ``8``], ``'best'` `: [``10``]}]` `# printing original list``print``(``"The original list : "` `+` `str``(test_list))` `# list comprehension to encapsulate logic in one liner``res ``=` `[]``[res.append(val) ``for` `val ``in` `test_list ``if` `val ``not` `in` `res]` `# printing result``print``(``"List after duplicates removal : "` `+` `str``(res))`

Output

```The original list : [{'Gfg': [2, 3], 'is': [7, 8], 'best': }, {'Gfg': [2, 3], 'is': , 'best': }, {'Gfg': [2, 3], 'is': [7, 8], 'best': }]
List after duplicates removal : [{'Gfg': [2, 3], 'is': [7, 8], 'best': }, {'Gfg': [2, 3], 'is': , 'best': }]```

Method 3: Using a set and tuple.

Step-by-step approach:

• Create an empty set to hold the unique values.
• Loop through each dictionary in the list.
• Convert the dictionary to a tuple, since sets can’t contain dictionaries.
• Check if the tuple is in the set of unique values. If it’s not, add it to the set and append the original dictionary to the result list.
• Print the result list.

## Python3

 `# Python3 code to demonstrate working of``# Unique Value Lists Dictionaries``# Using set and tuple` `# initializing lists``test_list ``=` `[{``'Gfg'``:  (``2``, ``3``), ``'is'` `: (``7``, ``8``), ``'best'` `: (``10``,)},``             ``{``'Gfg'``:  (``2``, ``3``), ``'is'` `: (``7``,), ``'best'` `: (``10``,)},``             ``{``'Gfg'``:  (``2``, ``3``), ``'is'` `: (``7``, ``8``), ``'best'` `: (``10``,)}]` `# printing original list``print``(``"The original list : "` `+` `str``(test_list))` `# set to hold unique values``unique_set ``=` `set``()` `# result list``res ``=` `[]` `# loop through each dictionary``for` `d ``in` `test_list:``    ``# convert dictionary to tuple``    ``d_tuple ``=` `tuple``(``sorted``(d.items()))``    ``# check if tuple is in unique set``    ``if` `d_tuple ``not` `in` `unique_set:``        ``# if not, add tuple to set and original dictionary to result list``        ``unique_set.add(d_tuple)``        ``res.append(d)` `# printing result``print``(``"List after duplicates removal : "` `+` `str``(res))`

Output

```The original list : [{'Gfg': (2, 3), 'is': (7, 8), 'best': (10,)}, {'Gfg': (2, 3), 'is': (7,), 'best': (10,)}, {'Gfg': (2, 3), 'is': (7, 8), 'best': (10,)}]
List after duplicates removal : [{'Gfg': (2, 3), 'is': (7, 8), 'best': (10,)}, {'Gfg': (2, 3), 'is': (7,), 'best': (10,)}]```

Time complexity: O(n log n) due to sorting the dictionaries into tuples.
Auxiliary space: O(n) for storing the unique values in a set and the result list.

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