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Python – Closest Pair to Kth index element in Tuple
• Last Updated : 10 Jun, 2020

Sometimes, while working with Python records, we can have a problem in which we need to find the tuple nearest to certain tuple, query on a particular index. This kind of problem can have application in data domains such as web development. Let’s discuss certain ways in which this task can be performed.

Input :
test_list = [(3, 4), (78, 76), (2, 3), (9, 8), (19, 23)]
tup = (17, 23)
K = 2

Output : (19, 23)
Input :
test_list = [(3, 4, 9), (5, 6, 7)]
tup = (1, 2, 5)
K = 3
Output : (5, 6, 7)

Method #1 : Using `enumerate() `+ loop
The combination of above functions offer brute force way to solve this problem. In this, we use enumerate() to monitor index and abs() to keep the minimum difference updated checked for each element over a loop.

 `# Python3 code to demonstrate working of ``# Closest Pair to Kth index element in Tuple``# Using enumerate() + loop`` ` `# initializing list``test_list ``=` `[(``3``, ``4``), (``78``, ``76``), (``2``, ``3``), (``9``, ``8``), (``19``, ``23``)]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initializing tuple``tup ``=` `(``17``, ``23``)`` ` `# initializing K ``K ``=` `1`` ` `# Closest Pair to Kth index element in Tuple``# Using enumerate() + loop``min_dif, res ``=` `999999999``, ``None``for` `idx, val ``in` `enumerate``(test_list):``    ``dif ``=` `abs``(tup[K ``-` `1``] ``-` `val[K ``-` `1``])``    ``if` `dif < min_dif:``        ``min_dif, res ``=` `dif, idx`` ` `# printing result ``print``(``"The nearest tuple to Kth index element is : "` `+` `str``(test_list[res])) `
Output :

```The original list is : [(3, 4), (78, 76), (2, 3), (9, 8), (19, 23)]
The nearest tuple to Kth index element is : (19, 23)
```

Method #2 : Using `min()` + lambda
The combination of above functions offer shorthand to solve this problem. In this, we use min() to find minimum element difference and lambda function is used to perform iterations and computations.

 `# Python3 code to demonstrate working of ``# Closest Pair to Kth index element in Tuple``# Using min() + lambda`` ` `# initializing list``test_list ``=` `[(``3``, ``4``), (``78``, ``76``), (``2``, ``3``), (``9``, ``8``), (``19``, ``23``)]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# initializing tuple``tup ``=` `(``17``, ``23``)`` ` `# initializing K ``K ``=` `1`` ` `# Closest Pair to Kth index element in Tuple``# Using min() + lambda``res ``=` `min``(``range``(``len``(test_list)), key ``=` `lambda` `sub: ``abs``(test_list[sub][K ``-` `1``] ``-` `tup[K ``-` `1``]))`` ` `# printing result ``print``(``"The nearest tuple to Kth index element is : "` `+` `str``(test_list[res])) `
Output :
```The original list is : [(3, 4), (78, 76), (2, 3), (9, 8), (19, 23)]
The nearest tuple to Kth index element is : (19, 23)
```

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