Python – Records with Value at K index
Sometimes, while working with records, we might have a problem in which we need to find all the tuples of elements for a particular value at a particular Kth position of tuple. This seems to be a peculiar problem but while working with many keys in records, we encounter this problem. Let’s discuss certain ways in which this problem can be solved.
Method #1 : Using loop
This is the brute force method by which this problem can be solved. In this we keep a check and append to list if we find specific record at Kth position in tuple.
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# Python3 code to demonstrate working of# Records with Value at K index# Using loop # initialize list test_list = [(3, 1, 5), (1, 3, 6), (2, 5, 7), (5, 2, 8), (6, 3, 0)] # printing original listprint("The original list is : " + str(test_list)) # initialize ele ele = 3 # initialize K K = 1 # Records with Value at K index# Using loop# using y for K = 1 res = []for x, y, z in test_list: if y == ele: res.append((x, y, z)) # printing resultprint("The tuples of element at Kth position : " + str(res)) |
The original list is : [(3, 1, 5), (1, 3, 6), (2, 5, 7), (5, 2, 8), (6, 3, 0)] The tuples of element at Kth position : [(1, 3, 6), (6, 3, 0)]
Method #2 : Using enumerate() + list comprehension
The combination of above functions can be used to solve this problem. In this, we enumerate for the indices using enumerate(), rest is performed as in above method but in compact way.
# Python3 code to demonstrate working of# Records with Value at K index# Using enumerate() + list comprehension # initialize list test_list = [(3, 1, 5), (1, 3, 6), (2, 5, 7), (5, 2, 8), (6, 3, 0)] # printing original listprint("The original list is : " + str(test_list)) # initialize ele ele = 3 # initialize K K = 1 # Records with Value at K index# Using enumerate() + list comprehensionres = [b for a, b in enumerate(test_list) if b[K] == ele] # printing resultprint("The tuples of element at Kth position : " + str(res)) |
The original list is : [(3, 1, 5), (1, 3, 6), (2, 5, 7), (5, 2, 8), (6, 3, 0)] The tuples of element at Kth position : [(1, 3, 6), (6, 3, 0)]
