# Python – List of N size increasing lists

Given integer N and M, construct increasing list till M, each list being N size i.e all combinations lists.

Input : N = 2, M = 3
Output : [(1, 2), (1, 3), (2, 3)]
Explanation : Increasing paired elements.

Input : N = 1, M = 4
Output : [(1, ), (2, ), (3, ), (4, )]
Explanation : Increasing paired elements.

Method #1 : Using loop

This is one brute force way in which this task can be performed. In this we iterate for elements till M, and form lists with N size. The drawback is that we are restricted to limited sized lists.

## Python3

 `# Python3 code to demonstrate working of  ` `# List of N size increasing lists ` `# Using loop ` ` `  `# initializing N ` `N ``=` `2` ` `  `# initializing M ` `M ``=` `4` ` `  `# outer loop manages lists ` `res ``=` `[] ` `for` `idx ``in` `range``(``1``, M): ` `     `  `    ``# inner loop manages inner elements ` `    ``for` `j ``in` `range``(idx ``+` `1``, M ``+` `1``): ` `        ``res.append((idx, j)) ` ` `  `# printing result  ` `print``(``"The constructed combinations : "` `+` `str``(res))  `

Output

```The constructed combinations : [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
```

Method #2 : Using combinations()

This is inbuild function offering exact functionality required for this solution. Solves the problem in one liner of getting increasing lists.

## Python3

 `# Python3 code to demonstrate working of  ` `# List of N size increasing lists ` `# Using combinations() ` `from` `itertools ``import` `combinations ` ` `  `# initializing N ` `N ``=` `2` ` `  `# initializing M ` `M ``=` `4` ` `  `# using combinations to perform task  ` `res ``=` `list``(combinations(``list``(``range``(``1``, M ``+` `1``)), N)) ` ` `  `# printing result  ` `print``(``"The constructed combinations : "` `+` `str``(res))  `

Output

```The constructed combinations : [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]

```

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