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Python program to interchange first and last elements in a list
• Difficulty Level : Basic
• Last Updated : 14 Nov, 2018

Given a list, write a Python program to swap first and last element of the list.

Examples:

```Input : [12, 35, 9, 56, 24]
Output : [24, 35, 9, 56, 12]

Input : [1, 2, 3]
Output : [3, 2, 1]
```

Approach #1: Find the length of the list and simply swap the first element with (n-1)th element.

 `# Python3 program to swap first ` `# and last element of a list ` ` `  `# Swap function ` `def` `swapList(newList): ` `    ``size ``=` `len``(newList) ` `     `  `    ``# Swapping  ` `    ``temp ``=` `newList[``0``] ` `    ``newList[``0``] ``=` `newList[size ``-` `1``] ` `    ``newList[size ``-` `1``] ``=` `temp ` `     `  `    ``return` `newList ` `     `  `# Driver code ` `newList ``=` `[``12``, ``35``, ``9``, ``56``, ``24``] ` ` `  `print``(swapList(newList)) `

Output:

`[24, 35, 9, 56, 12]`

Approach #2: The last element of the list can be referred as `list[-1]`. Therefore, we can simply swap `list` with `list[-1]`.

 `# Python3 program to swap first ` `# and last element of a list ` ` `  `# Swap function ` `def` `swapList(newList): ` `     `  `    ``newList[``0``], newList[``-``1``] ``=` `newList[``-``1``], newList[``0``] ` ` `  `    ``return` `newList ` `     `  `# Driver code ` `newList ``=` `[``12``, ``35``, ``9``, ``56``, ``24``] ` `print``(swapList(newList)) `

Output:

`[24, 35, 9, 56, 12]`

Approach #3: Swap the first and last element is using tuple variable. Store the first and last element as a pair in a tuple variable, say get, and unpack those elements with first and last element in that list. Now, the First and last values in that list are swapped.

 `# Python3 program to swap first ` `# and last element of a list ` ` `  `# Swap function ` `def` `swapList(``list``): ` `     `  `    ``# Storing the first and last element  ` `    ``# as a pair in a tuple variable get ` `    ``get ``=` `list``[``-``1``], ``list``[``0``] ` `     `  `    ``# unpacking those elements ` `    ``list``[``0``], ``list``[``-``1``] ``=` `get ` `     `  `    ``return` `list` `     `  `# Driver code ` `newList ``=` `[``12``, ``35``, ``9``, ``56``, ``24``] ` `print``(swapList(newList)) `

Output:

`[24, 35, 9, 56, 12]`

Approach #4: Using * operand.
This operand proposes a change to iterable unpacking syntax, allowing to specify a “catch-all” name which will be assigned a list of all items not assigned to a “regular” name.

 `# Python3 program to illustrate  ` `# the usage of * operarnd ` `list` `=` `[``1``, ``2``, ``3``, ``4``] ` ` `  `a, ``*``b, c ``=` `list` ` `  `print``(a) ` `print``(b) ` `print``(c) `

Output:

```1
[2, 3]
4```

Now let’s see the implementation of above approach:

 `# Python3 program to swap first ` `# and last element of a list ` ` `  `# Swap function ` `def` `swapList(``list``): ` `     `  `    ``start, ``*``middle, end ``=` `list` `    ``list` `=` `[end, ``*``middle, start] ` `     `  `    ``return` `list` `     `  `# Driver code ` `newList ``=` `[``12``, ``35``, ``9``, ``56``, ``24``] ` ` `  `print``(swapList(newList)) `

Output:

`[24, 35, 9, 56, 12]`

Approach #5: Swap the first and last elements is to use inbuilt function `list.pop()`. Pop the first element and store it in a variable. Similarily pop the last element and store it in another variable. Now insert the two popped element at each other’s original position.

 `# Python3 program to swap first ` `# and last element of a list ` ` `  `# Swap function ` `def` `swapList(``list``): ` `     `  `    ``first ``=` `list``.pop(``0``)    ` `    ``last ``=` `list``.pop(``-``1``) ` `     `  `    ``list``.insert(``0``, last)   ` `    ``list``.append(first)    ` `     `  `    ``return` `list` `     `  `# Driver code ` `newList ``=` `[``12``, ``35``, ``9``, ``56``, ``24``] ` ` `  `print``(swapList(newList)) `

Output:

`[24, 35, 9, 56, 12]`

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