In this python example, first we define an array and calculate sum of that array using different methods like using loop and sum function.

### Using Loop

In this method, we will create sum variable with 0 as it's value. Next, we will set loop on array or list. Then calculate and store element's value into sum variable.

Example - 1: using Loop

```    ```
#sum of arry elements in python using loop
def arraySum(arr):
sum = 0
for i in arr:
# shorthand of sum = sum + i
sum += i
return sum

print("Sum of array is ::",arraySum([1, 2, 3, 4, 5]))
```
```

Output :

```    ```
Sum of array is :: 15
```
```

Here we have created arraySum function so we can use this functionality often in our program.

### Using In-built sum() function

Python comes with an in-built solution for adding list or array and the sum() method simply returns the sum of each item of the gives list or array.

Example - 2: Using sum function

```    ```
#sum of array using sum function

arr = [1, 2, 3, 4, 5]

print("Sum of array is ::",sum(arr))
```
```

Output :

```    ```
Sum of array is :: 15
```
```

Here, we went through two different methods for sum the elements of an array however sum() function made our program faster and understandable.