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# Python Program to find sum of array

• Difficulty Level : Easy
• Last Updated : 04 Jan, 2023

Given an array of integers, find the sum of its elements.

Examples:

Input : arr[] = {1, 2, 3}
Output : 6
Explanation: 1 + 2 + 3 = 6

Input : arr[] = {15, 12, 13, 10}
Output : 50

Method 1: Iterating through the array and adding each element to the sum variable and finally displaying the sum.

## Python3

 `# Python 3 code to find sum` `# of elements in given array`     `def` `_sum(arr):`   `    ``# initialize a variable` `    ``# to store the sum` `    ``# while iterating through` `    ``# the array later` `    ``sum` `=` `0`   `    ``# iterate through the array` `    ``# and add each element to the sum variable` `    ``# one at a time` `    ``for` `i ``in` `arr:` `        ``sum` `=` `sum` `+` `i`   `    ``return``(``sum``)`     `# driver function` `arr ``=` `[]` `# input values to list` `arr ``=` `[``12``, ``3``, ``4``, ``15``]`   `# calculating length of array` `n ``=` `len``(arr)`   `ans ``=` `_sum(arr)`   `# display sum` `print``(``'Sum of the array is '``, ans)`

Output

```Sum of the array is  34
```

Time complexity: O(n),
Auxiliary Space: O(1)

Method 2: Using the built-in function sum(). Python provides an inbuilt function sum() which sums up the numbers in the list.

Syntax:

`sum(iterable) `

iterable: iterable can be anything list, tuples or dictionaries, but most importantly it should be numbered.

## Python3

 `# Python 3 code to find sum` `# of elements in given array` `# driver function` `arr ``=` `[]`   `# input values to list` `arr ``=` `[``12``, ``3``, ``4``, ``15``]`   `# sum() is an inbuilt function in python that adds` `# all the elements in list,set and tuples and returns` `# the value` `ans ``=` `sum``(arr)`   `# display sum` `print``(``'Sum of the array is '``, ans)`

Output

```Sum of the array is  34
```

Time complexity: O(n),
Auxiliary Space: O(1)

Method 2: Using the reduce method. Array.reduce() method is used to iterate over the array and get the summarized result from all elements of array.

Syntax:

`reduce( function, Array );`

## Python

 `from` `functools ``import` `reduce` `# Python 3 code to find sum` `# of elements in given array`     `def` `_sum(arr):`   `    ``# iterate over array` `    ``# using reduce and get ` `    ``# sum on accumulator` `    ``sum` `=` `reduce``(``lambda` `a, b: a``+``b, arr) `   `    ``return``(``sum``)`     `# driver function` `arr ``=` `[]` `# input values to list` `arr ``=` `[``12``, ``3``, ``4``, ``15``]`   `# calculating length of array` `n ``=` `len``(arr)`   `ans ``=` `_sum(arr)`   `# display sum` `print``(``'Sum of the array is '``, ans)`

Output

```('Sum of the array is ', 34)
```

Example: Using enumerate function

## Python3

 `list1 ``=` `[``12``, ``3``, ``4``, ``15``];s``=``0` `for` `i,a ``in` `enumerate``(list1): ` `  ``s``+``=``a ` `print``(s)`

Output

```34
```

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

Please refer complete article on Program to find sum of elements in a given array for more details!

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