Python – Extract records if Kth elements not in List
Given list of tuples, task is to extract all the tuples where Kth index elements are not present in argument list.
Input : test_list = [(5, 3), (7, 4), (1, 3), (7, 8), (0, 6)], arg_list = [6, 8, 8], K = 1
Output : [(5, 3), (7, 4), (1, 3)]
Explanation : All the elements which have either 6 or 8 at 1st index are removed.
Input : test_list = [(5, 3), (7, 4)], arg_list = [3, 3, 3, 3], K = 1
Output : [(7, 4)]
Explanation : (5, 3) is removed as it has 3 at 1st index.
Method #1 : Using set() + loop
This is one way in which this task can be. In this, we shorten the argument list using set and then efficiently check for Kth index having any element from arg. list and append accordingly.
Python3
# Python3 code to demonstrate working of # Extract records if Kth elements not in List # Using loop # initializing list test_list = [( 5 , 3 ), ( 7 , 4 ), ( 1 , 3 ), ( 7 , 8 ), ( 0 , 6 )] # printing original list print ( "The original list : " + str (test_list)) # initializing arg. list arg_list = [ 4 , 8 , 4 ] # initializing K K = 1 # Using set() to shorten arg list temp = set (arg_list) # loop to check for elements and append res = [] for sub in test_list: if sub[K] not in arg_list: res.append(sub) # printing result print ( "Extracted elements : " + str (res)) |
The original list : [(5, 3), (7, 4), (1, 3), (7, 8), (0, 6)] Extracted elements : [(5, 3), (1, 3), (0, 6)]
Method #2 : Using list comprehension + set()
This is yet another way in which this task can be performed. In this, we compile both, task of filtering duplicates using set() and compiling elements using conditionals inside list comprehension.
Python3
# Python3 code to demonstrate working of # Extract records if Kth elements not in List # Using list comprehension + set() # initializing list test_list = [( 5 , 3 ), ( 7 , 4 ), ( 1 , 3 ), ( 7 , 8 ), ( 0 , 6 )] # printing original list print ( "The original list : " + str (test_list)) # initializing arg. list arg_list = [ 4 , 8 , 4 ] # initializing K K = 1 # Compiling set() and conditionals into single comprehension res = [(key, val) for key, val in test_list if val not in set (arg_list)] # printing result print ( "Extracted elements : " + str (res)) |
The original list : [(5, 3), (7, 4), (1, 3), (7, 8), (0, 6)] Extracted elements : [(5, 3), (1, 3), (0, 6)]
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