Python: Make an iterator that returns consecutive keys and groups from the iterable

Last update on March 29 2025 13:02:55 (UTC/GMT +8 hours)

8. Consecutive Keys Group

Write a Python program to create an iterator that returns consecutive keys and groups from an iterable.

Sample Solution:

Python Code:

import itertools as it
print("Iterate over characters of a string and display\nconsecutive keys and groups from the iterable:")
str1 = 'AAAAJJJJHHHHNWWWEERRRSSSOOIIU'
data_groupby = it.groupby(str1)
for key, group in data_groupby:
    print('Key:', key)
    print('Group:', list(group))    
print("\nIterate over elements of a list and display\nconsecutive keys and groups from the iterable:")
str1 = 'AAAAJJJJHHHHNWWWEERRRSSSOOIIU'    
str1 = [1,2,2,3,4,4,5,5,5,6,6,7,7,7,8]
data_groupby = it.groupby(str1)
for key, group in data_groupby:
    print('Key:', key)
    print('Group:', list(group))

Sample Output:

Iterate over characters of a string and display
consecutive keys and groups from the iterable:
Key: A
Group: ['A', 'A', 'A', 'A']
Key: J
Group: ['J', 'J', 'J', 'J']
Key: H
Group: ['H', 'H', 'H', 'H']
Key: N
Group: ['N']
Key: W
Group: ['W', 'W', 'W']
Key: E
Group: ['E', 'E']
Key: R
Group: ['R', 'R', 'R']
Key: S
Group: ['S', 'S', 'S']
Key: O
Group: ['O', 'O']
Key: I
Group: ['I', 'I']
Key: U
Group: ['U']

Iterate over elements of a list and display
consecutive keys and groups from the iterable:
Key: 1
Group: [1]
Key: 2
Group: [2, 2]
Key: 3
Group: [3]
Key: 4
Group: [4, 4]
Key: 5
Group: [5, 5, 5]
Key: 6
Group: [6, 6]
Key: 7
Group: [7, 7, 7]
Key: 8
Group: [8]

For more Practice: Solve these Related Problems:

• Write a Python program to create an iterator that groups consecutive identical elements from an iterable using itertools.groupby.
• Write a Python program to iterate over an iterable, grouping consecutive elements that share a common property, and output the key with its group as a list.
• Write a Python program to build an iterator that returns consecutive keys and their corresponding grouped values from a sorted iterable.
• Write a Python program to generate groups of consecutive elements, then map a function to count the length of each group.

Python Code Editor:

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