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Python – Group list of tuples to dictionary

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  • Last Updated : 05 Jan, 2022
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Given a list of tuples, the task is to write a Python Program to get the dict into this tuple.

Example:

Input: [(1, 2, 3, 4, 5, 6), (1, 4), 
        (3, 5, 3, 4, 5, 6), (5, 7),
        (5, 6), (4, 4)]
Output:{1: [2, 3, 4, 5, 6, 4], 3: (5, 3, 4, 5, 6), 5: [7, 6], 4: [4]}

Example 1:

Create a list of tuples as shown. Then the task here is to group the list of tuples into a dictionary. For this purpose, Create an empty dictionary as shown. Then iterate through the list of tuples to group them to the dictionary.

Python3




# create a list of tuples.
test = [(1, 2), (1, 4), (3, 5), (5, 7)]
 
# create a empty dictionary name new_dict
new_dict = {}
 
# a for loop to iterate the list of tuples
for i in test:
   
    # checking whether the dictionary
    # has the key already.
    # If it returns No, a new Key is created.
    # If the key is not present the first
    # value of the tuple is made as the key
    if new_dict.get(i[0], 'No') == 'No':
       
      # THe remaining element is made
      # as values of the key
        new_dict[i[0]] = i[1:]
    else:
      # If the key is already present assign
      # the remaining element as values to
      # the corresponding key
        new_dict[i[0]] = new_dict.get(i[0]) + i[1:]
print(new_dict)


Output

{1: (2, 4), 3: (5,), 5: (7,)}

As you can see in the output, the list of tuples is grouped into a dictionary where the values are still a tuple of elements. 

Example 2: 

If you want the values of the dictionary to be a list, then, Create a new list of tuples. The task gain is to group the list of tuples into a dictionary. For this purpose, let’s create an empty dictionary as shown. Here, the dictionary values have to be a list. The key-value pairs with a single element in the value will still be as a tuple, so convert them to lists.

For a detailed explanation go through the code along with the comments below.

Python3




# create a list of tuples
test = [(1, 2, 3, 4, 5, 6), (1, 4),
        (3, 5, 3, 4, 5, 6), (5, 7),
        (5, 6), (4, 4)]
 
# create a empty dictionary name new_dict
new_dict = {}
 
# a for loop to iterate the list of tuples
for i in test:
   
    # checking whether the dictionary
    # has the key already.
    # If it returns No, a new Key is created.
    # If the key is not present the first
    # value of the tuple is made as the key
    if new_dict.get(i[0], 'No') == 'No':
       
          # THe remaining element is
        # made as values of the key
        new_dict[i[0]] = i[1:]
    else:
       
          # If the key is already present assign
        # the remaining element as values to
        # the corresponding key
          # add the values to the tuples and them
        # convert them to list using list() function
        new_dict[i[0]] = list(new_dict.get(i[0]) + i[1:])
 
# if the length of value is 1,
# it would be still as tuple,
# so convert them as list using list() function
for k, v in new_dict.items():
    if len(v) == 1:
        new_dict[k] = list(v)
print(new_dict)


Output

{1: [2, 3, 4, 5, 6, 4], 3: (5, 3, 4, 5, 6), 5: [7, 6], 4: [4]}

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