Python Program to find tuple indices from other tuple list

Last Updated : 07 Apr, 2021

Given Tuples list and search list consisting of tuples to search, our task is to write a Python Program to extract indices of matching tuples.

Input : test_list = [(4, 5), (7, 6), (1, 0), (3, 4)], search_tup = [(3, 4), (8, 9), (7, 6), (1, 2)]
Output : [3, 1]
Explanation : (3, 4) from search list is found on 3rd index on test_list, hence included in result.
Input : test_list = [(4, 5), (7, 6), (1, 0), (3, 4)], search_tup = [(3, 4), (8, 9), (7, 6), (1, 0)]

Output : [3, 1, 2]
Explanation : (3, 4) from search list is found on 3rd index on test_list, hence included in result.

Method #1 : Using lookup dictionary + enumerate() + list comprehension

In this, a lookup dictionary is formed to map all the tuples with matching one’s indices. Then lookup dictionary is used to get indices of mapped tuples as result using list comprehension.

Python3

# Python3 code to demonstrate working of
# Find tuple indices from other tuple list
# Using lookup dictionary + enumerate() + list comprehension
  
# initializing list
test_list = [(4, 5), (7, 6), (1, 0), (3, 4)]
               
# printing original list
print("The original list is : " + str(test_list))
  
# initializing search tuple 
search_tup = [(3, 4), (8, 9), (7, 6), (1, 2)]
  
# creating lookup_dict
lookup_dict = {val: key for key,val in enumerate(test_list)}
  
# creating result list
res = [lookup_dict[idx] for idx in search_tup if idx in lookup_dict]
  
# printing result
print("The match tuple indices : " + str(res))

Output:

The original list is : [(4, 5), (7, 6), (1, 0), (3, 4)]
The match tuple indices : [3, 1]

Method #2 : Using list comprehension + enumerate()

In this, we perform the task of getting indices using enumerate(), and list comprehension is used for the task of iteration of all the elements of tuple and matching for equality.

Python3

# Python3 code to demonstrate working of
# Find tuple indices from other tuple list
# Using list comprehension + enumerate()
  
# initializing list
test_list = [(4, 5), (7, 6), (1, 0), (3, 4)]
               
# printing original list
print("The original list is : " + str(test_list))
  
# initializing search tuple 
search_tup = [(3, 4), (8, 9), (7, 6), (1, 2)]
  
# enumerate() gets all the indices 
res = [idx for idx, val in enumerate(test_list) for ele in search_tup if ele == val]
  
# printing result
print("The match tuple indices : " + str(res))

Output:

The original list is : [(4, 5), (7, 6), (1, 0), (3, 4)]
The match tuple indices : [1, 3]

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