**Problem**: How to create a sequence of evenly-spaced values

- Using pure, vanilla Python, and
- Using NumPy’s
`linspace()`

method.

**Example**: Given three arguments: **start=10,**** stop=20**,

**. How do you create a sequence of 11 values**

*number_of_values=11***where two subsequent values**

*x0, x1, …, x10***and**

*xi***have the same distance for all**

*x(i-1)***in**

*i***.**

*{0, …, 10}*

# Given`start = 10 stop = 20 num_vals = 11`

# Desiredmagic_method(start, stop, num_vals) # Returns[10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]

Next, you’ll learn two methods that accomplish this goal!

Table of Contents

## Method 1: Vanilla Python

You can create a sequence of a certain number of evenly spaced floats in two steps:

- Calculate the difference between two subsequent numbers as
`(stop-start)/(num_vals-1)`

assuming you want to include endpoints. - Create a list of evenly spaced numbers using list comprehension:
`[start + i * delta for i in range(num_vals)]`

# Problem Formulation start = 10 stop = 20 num_vals = 11 # Method 1: Vanilla Python delta = (stop-start)/(num_vals-1) evenly_spaced = [start + i * delta for i in range(num_vals)] print(evenly_spaced)

## Method 2: NumPy linspace()

How does it work? Have a look at this graphic that explains NumPy’s linspace function visually:

It takes only three arguments in most cases: `start`

, `stop`

, and `num`

. To accomplish the goal, you’d use the following code:

# Problem Formulation start = 10 stop = 20 num_vals = 11 # Method 2: NumPy Linspace import numpy as np print(np.linspace(start, stop, num_vals)) # [10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.]

Note that the result is a list of floats. To convert them to an int, you can use the following one-liner instead:

print([int(x) for x in np.linspace(start, stop, num_vals)]) # [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]

## NumPy linspace() Puzzle

Can you solve this Python puzzle?

[python]

import numpy as np

year = np.linspace(0, 365, 366)

print(int(year[-1] – year[-2]))

[/python]

**Exercise**: *What is the output of this puzzle?*

You can also solve it on our interactive Python puzzle app and track your Python skills here:

Numpy is a popular Python library for data science focusing on linear algebra.

This puzzle is about the useful function linspace. In particular, `linspace(start, stop, num)`

returns evenly spaced numbers over a given interval `[start, stop]`

, with stop included.

For example, `linspace(0,3,4)`

returns the numpy array sequence 0,1,2,3 (i.e., 4 evenly spaced numbers).

This function is particularly useful when plotting (or evaluating) a function. The result of the function applied to evenly spaced numbers reveals how it progresses for growing parameter values.

## Related Video

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com. He’s author of the popular programming book Python One-Liners (NoStarch 2020), coauthor of the Coffee Break Python series of self-published books, computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.