# Python | Check if list contains consecutive numbers

• Last Updated : 19 Mar, 2019

Given a list of numbers, write a Python program to check if the list contains consecutive integers.

Examples:

```Input : [2, 3, 1, 4, 5]
Output : True

Input : [1, 2, 3, 5, 6]
Output : False
```

Let’s discuss the few ways we can do this task.

Approach #1 : using `sorted()`

This approach uses `sorted()` function of Python. We compare the sorted list with list of range of minimum and maximum integer of the list and return it.

 `# Python3 Program to Create list ``# with integers within given range `` ` `def` `checkConsecutive(l):``    ``return` `sorted``(l) ``=``=` `list``(``range``(``min``(l), ``max``(l)``+``1``))``     ` `# Driver Code``lst ``=` `[``2``, ``3``, ``1``, ``4``, ``5``]``print``(checkConsecutive(lst))`

Output:

```True
```

Approach #2 : Using `numpy.diff()`

Numpy module provides a function `diff()` that calculate the n-th discrete difference along the given axis. We find the iterative difference of the sorted list and check if it is equal to 1.

 `# Python3 Program to Create list ``# with integers within given range ``import` `numpy as np`` ` `def` `checkConsecutive(l):``    ``n ``=` `len``(l) ``-` `1``    ``return` `(``sum``(np.diff(``sorted``(l)) ``=``=` `1``) >``=` `n) ``     ` `# Driver Code``lst ``=` `[``2``, ``3``, ``1``, ``4``, ``5``]``print``(checkConsecutive(lst))`

Output:

```True
```

My Personal Notes arrow_drop_up