## (Python Tutorials for Citizen Data Scientist)

# Python Code to Check Prime Number

#### Example to check whether an integer is a prime number or not using for loop and if…else statement. If the number is not prime, it’s explained in output why it is not a prime number.

A positive integer greater than 1 which has no other factors except 1 and the number itself is called a prime number. 2, 3, 5, 7 etc. are prime numbers as they do not have any other factors. But 6 is not prime (it is composite) since, `2 x 3 = 6`

.

## Source Code

```
# Program to check if a number is prime or not
num = 407
# To take input from the user
#num = int(input("Enter a number: "))
# prime numbers are greater than 1
if num > 1:
# check for factors
for i in range(2,num):
if (num % i) == 0:
print(num,"is not a prime number")
print(i,"times",num//i,"is",num)
break
else:
print(num,"is a prime number")
# if input number is less than
# or equal to 1, it is not prime
else:
print(num,"is not a prime number")
```

**Output**

407 is not a prime number 11 times 37 is 407

In this program, variable num is checked if it’s prime or not. Numbers less than or equal to 1 are not prime numbers. Hence, we only proceed if the `num` is greater than 1.

We check if `num` is exactly divisible by any number from 2 to num – 1. If we find a factor in that range, the number is not prime. Else the number is prime.

We can decrease the range of numbers where we look for factors.

In the above program, our search range is from 2 to `num - 1`

.

We could have used the range, `range(2,num//2)`

or `range(2,math.floor(math.sqrt(num)))`

. The latter range is based on the fact that a composite number must have a factor less than the square root of that number. Otherwise, the number is prime.

You can change the value of variable `num` in the above source code to check whether a number is prime or not for other integers.

Python tutorials for Business Analyst – Python if…else Statement

## Python Examples for Beginners: Python Code to Check if a Number is Odd or Even

Disclaimer: The information and code presented within this recipe/tutorial is only for educational and coaching purposes for beginners and developers. Anyone can practice and apply the recipe/tutorial presented here, but the reader is taking full responsibility for his/her actions. The author (content curator) of this recipe (code / program) has made every effort to ensure the accuracy of the information was correct at time of publication. The author (content curator) does not assume and hereby disclaims any liability to any party for any loss, damage, or disruption caused by errors or omissions, whether such errors or omissions result from accident, negligence, or any other cause.The information presented here could also be found in public knowledge domains.

# Learn by Coding: v-Tutorials on Applied Machine Learning and Data Science for Beginners

Latest end-to-end Learn by Coding Projects (Jupyter Notebooks) in Python and R:

**All Notebooks in One Bundle: Data Science Recipes and Examples in Python & R****. **

**End-to-End Python Machine Learning Recipes & Examples.**

**End-to-End R Machine Learning Recipes & Examples.**

**Applied Statistics with R for Beginners and Business Professionals**

**Data Science and Machine Learning Projects in Python: Tabular Data Analytics**

**Data Science and Machine Learning Projects in R: Tabular Data Analytics**

**Python Machine Learning & Data Science Recipes: Learn by Coding**

**R Machine Learning & Data Science Recipes: Learn by Coding**

**Comparing Different Machine Learning Algorithms in Python for Classification (FREE)**

There are 2000+ End-to-End Python & R Notebooks are available to build **Professional Portfolio as a Data Scientist and/or Machine Learning Specialist**. All Notebooks are only $29.95. We would like to request you to have a look at the website for FREE the end-to-end notebooks, and then decide whether you would like to purchase or not.