Sum () function in Python

The built-in function sum () in Python returns the sum of all numbers in iterable.

Sum function sum ()

 sum(iterable, start) 

The sum () function starts adding from left to right

1. iterable : built-in iterable (like list, string, dict) needs to be summed, usually numbers.
2. start : value added to the value returned from iterable. The default value is 0.

Value returned from sum ()

The sum () function returns the sum of start and iterable component items.

For example: How sum () works in Python

 numbers = [2.5, 3, 4, -5] 
 
 # không truyền tham số start 
 numbersSum = sum(numbers) 
 print(numbersSum) 
 
 # start = 10 
 numbersSum = sum(numbers, 10) 
 print(numbersSum) 

Run the program, the result is:

 4.5 
 14.5 

See also: Built-in Python functions