# Master Python's range() and len() Functions for Maximum Efficiency

This guide explains how to use Python's range() and len() functions to maximize efficiency while writing code.

## Introduction

Python's range() and len() functions are useful tools for optimizing code and increasing productivity. range() allows you to select portions of a sequence by providing numerical boundaries, whereas len() helps you to figure out the length of a sequence quickly and accurately.

## Usage

### range()

#### Syntax

``````range(start, stop[, step])
``````

#### Explanation

The range() function creates a sequence of numbers. The first parameter `start` is the beginning of the sequence and the second parameter `stop` is the number immediately after the last number in the sequence. The sequence can also be specified with a third parameter `step` which is the amount added to each number as the sequence progresses. The default value for step is 1.

#### Examples

For example, if you want to create a sequence of numbers from 1 to 10, you would enter

``````range(1, 11)
``````

to get the following sequence:

``````(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
``````

Using the `step` parameter, if you only wanted to get odd numbers from 1 to 10, you would use

``````range(1, 11, 2)
``````

to get the following sequence:

``````(1, 3, 5, 7, 9)
``````

### len()

#### Syntax

``````len(object)
``````

#### Explanation

The len() function returns the length of an object. It is useful for determining the length of a sequence, iterable, or related object.

#### Examples

For example, if you wanted to get the length of the list below, you would use

``````list = [3, 5, 7, 8, 10]

len(list)
``````

to get the following output:

``````5
``````

## FAQ

Q: Can I use the range() function with negative numbers?

A: Yes, you can use the range() function with negative numbers as long as your `stop` parameter is greater than the `start` parameter.

Q: What happens when I try to use the len() function with a string?

A: The len() function will return the length of a string in terms of the number of characters in the string.

## Sources

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