# Python | Sum of squares in list

• Last Updated : 08 Feb, 2023

Python being the language of magicians can be used to perform many tedious and repetitive tasks in a easy and concise manner and having the knowledge to utilize this tool to the fullest is always useful. One such small application can be finding sum of squares of list in just one line. Let’s discuss certain ways in which this can be performed.

Method #1 : Using reduce() + lambda The power of lambda functions to perform lengthy tasks in just one line, allows it combined with reduce which is used to accumulate the subproblem, to perform this task as well. Works with only Python 2.

## Python

 `# Python code to demonstrate``# sum of squares``# using reduce() + lambda` `# initializing list``test_list ``=` `[``3``, ``5``, ``7``, ``9``, ``11``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))` `# using reduce() + lambda``# sum of squares``res ``=` `reduce``(``lambda` `i, j: i ``+` `j ``*` `j, [test_list[:``1``][``0``]``*``*``2``]``+``test_list[``1``:])` `# printing result``print``(``"The sum of squares of list is : "` `+` `str``(res))`

Output

```The original list is : [3, 5, 7, 9, 11]
The sum of squares of list is : 285```

Time complexity: The reduce function in this code has a time complexity of O(n), where n is the number of elements in the input list “test_list”. The lambda function used inside the reduce function takes constant time to execute, so the overall time complexity is O(n).
Auxiliary Space: The reduce function in this code has an auxiliary space complexity of O(1), as it only requires a single accumulator variable to store the intermediate and final results. The lambda function used inside the reduce function takes constant space, so the overall auxiliary space complexity is O(1).

Method #2 : Using map() + sum() The similar solution can also be obtained using the map function to integrate and sum function to perform the summation of the squared number.

## Python3

 `# Python3 code to demonstrate``# sum of squares``# using sum() + max()` `# initializing list``test_list ``=` `[``3``, ``5``, ``7``, ``9``, ``11``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))` `# using sum() + max()``# sum of squares``res ``=` `sum``(``map``(``lambda` `i: i ``*` `i, test_list))` `# printing result``print``(``"The sum of squares of list is : "` `+` `str``(res))`

Output

```The original list is : [3, 5, 7, 9, 11]
The sum of squares of list is : 285```

Time Complexity: O(n)
Auxiliary Space: O(1)

Method #3 : Using for loop and math.pow()

## Python3

 `# Python3 code to demonstrate``# sum of squares` `# initializing list``test_list ``=` `[``3``, ``5``, ``7``, ``9``, ``11``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`  `# sum of squares``res ``=` `0``for` `i ``in` `test_list:``    ``from` `math ``import` `pow``    ``res ``+``=` `pow``(i, ``2``)``res ``=` `int``(res)``# printing result``print``(``"The sum of squares of list is : "` `+` `str``(res))`

Output

```The original list is : [3, 5, 7, 9, 11]
The sum of squares of list is : 285```

Method : Using simple list comprehension

Here is an approach using a list comprehension:

## Python3

 `# initializing list``test_list ``=` `[``3``, ``5``, ``7``, ``9``, ``11``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))` `# using list comprehension``# sum of squares``res ``=` `sum``([i``*``*``2` `for` `i ``in` `test_list])` `# printing result``print``(``"The sum of squares of list is : "` `+` `str``(res))` `# This code is contributed by Edula Vinay Kumar Reddy`

Output

```The original list is : [3, 5, 7, 9, 11]
The sum of squares of list is : 285```

Method #5: Using numpy

## Python3

 `import` `numpy as np` `test_list ``=` `np.array([``3``, ``5``, ``7``, ``9``, ``11``])` `# printing original list``print``(``"The original list is : "``, test_list)` `# using NumPy``# sum of squares``res ``=` `np.``sum``(np.square(test_list))` `# printing result``print``(``"The sum of squares of list is : "``, res)``#This code is contributed by jyothi pinjala.`

Output:

```The original list is : [3, 5, 7, 9, 11]
The sum of squares of list is : 285```

Time Complexity: O(N)
Auxiliary Space : O(1)

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