Python | Sort Tuples in Increasing Order by any key
Last Updated :
14 Apr, 2023
Given a tuple, sort the list of tuples in increasing order by any key in tuple. Examples:
Input : tuple = [(2, 5), (1, 2), (4, 4), (2, 3)]
m = 0
Output : [(1, 2), (2, 3), (2, 5), (4, 4)]
Explanation: Sorted using the 0th index key.
Input : [(23, 45, 20), (25, 44, 39), (89, 40, 23)]
m = 2
Output : Sorted: [(23, 45, 20), (89, 40, 23), (25, 44, 39)]
Explanation: Sorted using the 2nd index key
Given tuples, we need to sort them according to any given key. This can be done using sorted() function where we sort them using key=last and store last as the key index according to which we have to sort the given tuples. Below is the Python implementation of the above approach:
Python
def last(n):
return n[m]
def sort(tuples):
return sorted(tuples, key = last)
a = [(23, 45, 20), (25, 44, 39), (89, 40, 23)]
m = 2
print("Sorted:"),
print(sort(a))
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Output:
Sorted: [(23, 45, 20), (89, 40, 23), (25, 44, 39)]
Another approach is using the operator.itemgetter() function from the operator module. The itemgetter() function returns a callable object that can be used to retrieve an item from an object, such as a tuple.
Here is an example of how to use itemgetter() to sort a list of tuples by any key:
Python3
import operator
def sort_tuples(tuples, key):
return sorted(tuples, key=operator.itemgetter(key))
tuples = [(2, 5), (1, 2), (4, 4), (2, 3)]
key = 0
print(sort_tuples(tuples, key))
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Output
[(1, 2), (2, 5), (2, 3), (4, 4)]
This approach has the advantage of being concise and efficient, as it uses the built-in sorted() function and the itemgetter() function from the operator module. It is also easy to understand and implement.
Note that the itemgetter() function returns a callable object that can be used to retrieve an item from an object, such as a tuple. To sort the tuples, we pass this callable object to the key argument of the `sorted
Approach#3: Using lambda
One way to sort tuples in increasing order by any key is to use the sorted function and pass a key function that returns the desired element of each tuple.
Algorithm
1. Define a key function that returns the desired element of each tuple.
2. Use the sorted function to sort the list of tuples using the key function.
Python3
def sort_tuples(tuples, key_idx):
key_func = lambda x: x[key_idx]
sorted_tuples = sorted(tuples, key=key_func)
return sorted_tuples
tuples = [(2, 5), (1, 2), (4, 4), (2, 3)]
sorted_tuples = sort_tuples(tuples, 0)
print(sorted_tuples)
tuples = [(23, 45, 20), (25, 44, 39), (89, 40, 23)]
sorted_tuples = sort_tuples(tuples, 2)
print(sorted_tuples)
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Output
[(1, 2), (2, 5), (2, 3), (4, 4)]
[(23, 45, 20), (89, 40, 23), (25, 44, 39)]
Time Complexity: O(n log n), where n is the number of tuples in the list. This is because sorting takes O(n log n) time in the worst case.
Space Complexity: O(n), where n is the number of tuples in the list. This is because we create a new sorted list of tuples.
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