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Python | Minimum key equal pairs
• Last Updated : 27 Dec, 2019

Sometimes, while working with Python, we can have a problem in which we need to get all the records. This data can have similar values and we need to find minimum key’ed value pair. This kind of problem can occur while working with data. Let’s discuss certain ways in which this task can be done.

Method #1 : Using `min() + groupby() + itemgetter()` + list comprehension

The combination of above functions can be used to perform this particular task. In this, we first group the like valued elements using groupby() and itemgetter(), and then extract the minimum of those using min() and cummulate the result in list using list comprehension.

 `# Python3 code to demonstrate working of ` `# Minimum key equal pairs ` `# using min() + groupby() + itemgetter() + list comprehension ` `from` `operator ``import` `itemgetter ` `from` `itertools ``import` `groupby ` ` `  `# initialize list ` `test_list ``=` `[(``4``, ``3``), (``2``, ``3``), (``3``, ``10``), (``5``, ``10``), (``5``, ``6``)] ` ` `  `# printing original list ` `print``(``"The original list : "` `+` `str``(test_list)) ` ` `  `# Minimum key equal pairs ` `# using min() + groupby() + itemgetter() + list comprehension ` `res ``=` `[``min``(values) ``for` `key, values ``in` `groupby(test_list, key ``=` `itemgetter(``1``))] ` ` `  `# printing result ` `print``(``"Minimum key equal pairs : "` `+` `str``(res)) `

Output :

```The original list : [(4, 3), (2, 3), (3, 10), (5, 10), (5, 6)]
Minimum key equal pairs : [(2, 3), (3, 10), (5, 6)]
```

Method #2 : Using `setdefault() + items()` + loop + list comprehension

The combination of above functions can also achieve this task. In this, we convert the list tuple key-value pairs into a dictionary and assign a default value using setdefault(). The final result is computed using list comprehension.

 `# Python3 code to demonstrate working of ` `# Minimum key equal pairs ` `# using setdefault() + items() + loop + list comprehension ` ` `  `# initialize list ` `test_list ``=` `[(``4``, ``3``), (``2``, ``3``), (``3``, ``10``), (``5``, ``10``), (``5``, ``6``)] ` ` `  `# printing original list ` `print``(``"The original list : "` `+` `str``(test_list)) ` ` `  `# Minimum key equal pairs ` `# using setdefault() + items() + loop + list comprehension ` `temp ``=` `{} ` `for` `val, key ``in` `test_list: ` `    ``if` `val < temp.setdefault(key, val): ` `        ``temp[key] ``=` `val ` `res ``=` `[(val, key) ``for` `key, val ``in` `temp.items()] ` ` `  `# printing result ` `print``(``"Minimum key equal pairs : "` `+` `str``(res)) `

Output :

```The original list : [(4, 3), (2, 3), (3, 10), (5, 10), (5, 6)]
Minimum key equal pairs : [(2, 3), (3, 10), (5, 6)]
```

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