Sometimes mistakenly used interchangeably, we’re here to tell you that a **parameter** is not a **variable**.

However, depending on the context – a parameter and a variable can mean many different things.

In this post, we’ll break down the following:

- Difference between a parameter and variable (General)
- Difference between a parameter and variable (Data Science)
- An example of both of the above
- And some frequently asked questions to help solidify the knowledge

Hang on; it’ll be a bumpy ride (at first).

**Table of Contents**show

What is the difference between a parameter and a variable?

While these terms are almost used interchangeably, there are some subtle differences.

For example, in a general mathematical equation:

y= mx + b

m and b are the parameters of this equation.

This equation is still “loosely” defined, and once we assign some **values to the parameters (like m=4, b=5), the equation is now limited to some domain.**

With our equation defined, we now have the following:

y = 4x + 5

We can now **pass numbers to our variable (x)**, as the domain of this function has been set.

While it feels simple, it can still get a little choppy when we extend this idea into computer science.

What is an example of a parameter and variable?

Here we have a parameter of an equation utilizing the same idea as above.

m and b are our parameters, which we can pass any value into.

We have a variable in the equation, which is x = 4.

While we can pass any values into our parameters (arguments), our variable will never change.

Note there are different types of variables called global and local (we go over more about these at the end).

Now that you know the difference between a variable and a parameter in general, We can branch off mathematics and computer science into other related fields.

What is the difference between a parameter and a variable in Data Science?

In data science, the difference between variables and parameters is not similar and is only loosely connected.

In data science, when someone says “variables,” they’re probably referring to your independent variables.

These are the variables commonly used to build models (or multiple models) to predict your dependent variable.

For example, in the image below:

**remote_ratio**and

**company_size**would be our independent variables, while

**salary_in_usd**is our dependent variable.

**variables**from above, just now one-hot encoded.

**dependent variable,**which gives us a model.

**parameters**from the model, which in this case, were the coefficients for each

**variable**in our linear regression model.

It’s okay, you’ll probably need to re-read that a couple of times.

Frequently Asked Questions

These two terms can get confusing; we hope some of the questions below help clarify things.

## Does a variable have parameters?

A variable can have parameters. If a variable is defined as a function, that function could have parameters. A variable does not have to be a function and could just be a scalar (number).

## What does it mean when a variable is a parameter?

Sometimes, variables are passed into an equation. In standard software engineering, most teams take a modular approach, which means using functions to solve different parts of code. Many times, variables defined within one function will need to be passed as a parameter to another function, which can happen to many different variables.

## Is a parameter a constant or a variable?

A parameter can be a constant or a variable. In Python, you can define parameters with fall-back values, which take the form of variables but can also be constant numbers.

## Do variables have parameters in Python?

In Python, variables defined within one function will sometimes need to be passed as a parameter to another function. This can happen to many different variables, all inside one function.

## Is a parameter fixed or variable?

Each function fixes parameters. These parameters will not be changed unless someone changes the code. Different variables can be passed to these parameters, changing the local values of the variables.

## What makes a value a parameter?

A value becomes a parameter when it’s used to scope some function. It doesn’t matter if it’s in mathematics or computer science; if defining values for part of your equation creates a domain, that value is a parameter.

## Are parameters local variables?

Parameters are not local variables. Local variables exist inside functions, which are different from global variables, which are available to all functions everywhere. Many times variables passed into parameters help define these local variables.

More Articles In Our Machine Learning 101 Series

We have many straightforward guides that go over some of the essential parts of machine learning.

Some of those guides include:

- Reverse Standardization For ML Models: Another staple in our 101 series is an introductory article teaching you about scaling and standardization.
- Criterion And Predictor: One of the first steps in statistical testing is the independent and dependent variables.
- Heatmaps in Python: Visualizing your data is data science 101. Don’t miss this one.
- SelectKBest For Feature Selection (Sklearn): Feature selection is pivotal in machine learning; make sure to check it out here.
- CountVectorizer and TfidfVectorizer: Interested in learning NLP? This article gives a thorough deep dive.
- Normal Distribution and the Uniform Distribution: Little rusty on normal distributions? We have an article here about it.
- Welch’s T-Test: Do you know the difference between the student’s t-test and welch’s t-test? Don’t worry, we explain it in-depth here.
- Gini Index and Entropy: Understanding these two fundamental parts of decision trees is key for data science!

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- 9 Best Processors For Data Science and Machine Learning [That Won’t Break The Bank] - December 3, 2022
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