Python sum() function

The sum() function in Python is used when we need to find the sum of all items available in an iterable such as a list, tuple, etc. For example:

x = [1, 2, 3, 4, 5]
print(sum(x))

x = (12, 23, 34, 54)
print(sum(x))

The output is:

15
123

Python sum() function syntax

The syntax of the sum() function in Python is:

sum(iterable, value)

The "value" parameter is optional and is used when we need to add extra value to the result returned by sum().

Note: The iterable should contain numbers to perform the addition of all of its items using the sum() function.

Python sum() function example

Here is an example of the sum() function in Python:

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

print(sum(x))
print(sum(x, 5))
print(sum(x, 10))
print(sum(x, 100))
print(sum([1, 2, 3, 4, 5], 100))

x = {1: "Name", 2: "University", 3: "Course"}
print(sum(x))

The output is:

15
20
25
115
115
6

If you use the dictionary as an iterable, then its key will be used.

Advantages of the sum() function in Python

• The sum() function is a simple and convenient way to find the sum of an iterable's elements without having to write a loop or use other more complex functions.
• The sum() function is optimized for performance and can quickly process large amounts of data, making it an excellent choice for performance-sensitive code.
• The sum() function can be used with a wide range of iterables, including lists, tuples, sets, and generators, making it a versatile tool applicable in a variety of situations.

Disadvantages of the sum() function in Python

• Precision: The sum() function may experience precision issues with floating-point numbers, leading to unexpected rounding errors. Due to how floating-point numbers are represented in memory, the sum of a list of floating-point numbers may not produce an exact result.
• If the iterable passed to sum() contains non-numerical elements, like strings or other objects, the function will throw a TypeError. If the input data is not thoroughly validated beforehand, this can result in unintended behavior.
• While the sum() function is useful for calculating the sum of an iterable's elements, it has limited functionality beyond this basic operation. It cannot, for instance, perform more complex mathematical operations or apply custom functions to an iterable's elements.

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