# Python Program to Print all Happy Numbers within a given Range

In this article, we will learn how to print happy numbers within a specific range in Python. You will learn what a happy number is, how to check whether a given number is a happy number, and how to write Python code that outputs all the happy numbers within the user-specified range.

Happy Number :

If the repeating sum of the digits squared equals one, the number is said to be a Happy Number. If we continue this method and get outcome 1, we have a happy number. If the outcome is 4, it enters an infinite loop and is not a happy number. Let’s look at an example to help you grasp it better.

Given Number = 320
Square of the digits  = 3+ 22 + 0= 13
Square of the digits  = 12 + 32 = 10
Square of the digits  = 12 + 02 = 1

Other Examples of happy numbers  =7, 28, 100 etc.

Examples:

Example1:

Input:

Given upper limit range =19
Given lower limit range =145

Output:

The happy numbers in the given range 19 and 145 are:
19 23 28 31 32 44 49 68 70 79 82 86 91 94 97 100 103 109 129 130 133 139

Example2:

Input:

Given upper limit range =333
Given lower limit range =444

Output:

The happy numbers in the given range 333 and 444 are:
338 356 362 365 367 368 376 379 383 386 391 392 397 404 409 440

## Program to Print all Happy numbers within a given range in Python

Below are the ways to print all the happy numbers in the given range.

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### Method #1: Using For Loop (Static Input)

Approach:

• Create a function checkhapppynumb() which accepts the number as an argument and returns true if it is happy number else returns False.
• Give the lower limit range as static input and store it in a variable.
• Give the upper limit range as static input and store it in another variable.
• Create a function digitSquareSum() that accepts the given number as an argument and returns the sum of squares of digits.
• Inside the digitSquareSum() function.
• Convert the given argument to string using the str() function.
• Convert the given argument into list of digits using list(),map(),int() functions.
• Store it in a variable.
• Take a variable sumsquaredigits and initialize its value to 0.
• Loop in this digits list using For loop.
• Increment the value of sumsquaredigits by the square of the digit(iterator value).
• Return the sumsquaredigits value.
• Loop from lower limit range to upper limit range using For loop.
• Inside the for loop pass the iterator value to checkhapppynumb() function.
• Inside the checkhapppynumb() function.
• Take a variable reslt and initialize its value to the given argument.
• Loop till the reslt is not equal to 1 or 4 using while loop.
• Inside the loop pass the reslt value to digitSquareSum() and store it in the same variable reslt.
• After the end of the while loop, Check whether reslt value is 1 or not using the If statement.
• If it is true then the given number is a happy number so return True
• Else it is not a happy number so return False.
• If it returns true then print the iterator value with space.
• The Exit of the Program.

Below is the implementation:

# Create a function digitSquareSum() that accepts the given number
# as an argument and returns the sum of squares of digits.

def digitSquareSum(resltnumber):
# Inside the digitSquareSum() function.
# Convert the given argument to string using the str() function.
strnumbe = str(resltnumber)
# Convert the given argument into list of digits using list(),map(),int() functions.
# Store it in a variable.
numbrlistdigits = list(map(int, strnumbe))
# Take a variable sumsquaredigits and initialize its value to 0.
sumsquaredigits = 0
# Loop in this digits list using For loop.
for digitvalu in numbrlistdigits:
# Increment the value of sumsquaredigits by the square
# of the digit(iterator value).
sumsquaredigits = sumsquaredigits+(digitvalu**2)
# Return the sumsquaredigits value
return sumsquaredigits

# Create a function checkhapppynumb() which accepts the number as an argument
# and returns true if it is happy number else returns False.

def checkhapppynumb(numb):
# Take a variable rest and initialize its value to the given argument.
rest = numb
# Loop till the rest is not equal to 1 or 4 using while loop.
while(rest != 1 and rest != 4):
# Inside the loop pass the reslt value to digitSquareSum()
# and store it in the same variable reslt.
rest = digitSquareSum(rest)
# After the end of the while loop,
# Check whether rest value is 1 or not using the If statement.
if(rest == 1):
# If it is true then the given number is a happy number so return True
return True
else:
# Else it is not a happy number so return False.
return False

# Give the lower limit range as static input and store it in a variable.
lowlimrange = 19
# Give the upper limit range as static input and store it in another variable.
upplimrange = 145
print('The happy numbers in the given range',
lowlimrange, 'and', upplimrange, 'are:')
# Loop from lower limit range to upper limit range using For loop.
for l in range(lowlimrange, upplimrange+1):
# IInside the for loop pass the iterator value to checkhapppynumb() function.
if(checkhapppynumb(l)):
# If it returns true then print the iterator value.
print(l, end=' ')


Output:

The happy numbers in the given range 19 and 145 are:
19 23 28 31 32 44 49 68 70 79 82 86 91 94 97 100 103 109 129 130 133 139

### Method #2: Using For Loop (User Input)

Approach:

• Create a function checkhapppynumb() which accepts the number as an argument and returns true if it is happy number else returns False.
• Give the lower limit range and upper limit range as user input using map(),int(),split() functions.
• Store them in two separate variables.
• Create a function digitSquareSum() that accepts the given number as an argument and returns the sum of squares of digits.
• Inside the digitSquareSum() function.
• Convert the given argument to string using the str() function.
• Convert the given argument into list of digits using list(),map(),int() functions.
• Store it in a variable.
• Take a variable sumsquaredigits and initialize its value to 0.
• Loop in this digits list using For loop.
• Increment the value of sumsquaredigits by the square of the digit(iterator value).
• Return the sumsquaredigits value.
• Loop from lower limit range to upper limit range using For loop.
• Inside the for loop pass the iterator value to checkhapppynumb() function.
• Inside the checkhapppynumb() function.
• Take a variable reslt and initialize its value to the given argument.
• Loop till the reslt is not equal to 1 or 4 using while loop.
• Inside the loop pass the reslt value to digitSquareSum() and store it in the same variable reslt.
• After the end of the while loop, Check whether reslt value is 1 or not using the If statement.
• If it is true then the given number is a happy number so return True
• Else it is not a happy number so return False.
• If it returns true then print the iterator value.
• The Exit of the Program.

Below is the implementation:

# Create a function digitSquareSum() that accepts the given number
# as an argument and returns the sum of squares of digits.

def digitSquareSum(resltnumber):
# Inside the digitSquareSum() function.
# Convert the given argument to string using the str() function.
strnumbe = str(resltnumber)
# Convert the given argument into list of digits using list(),map(),int() functions.
# Store it in a variable.
numbrlistdigits = list(map(int, strnumbe))
# Take a variable sumsquaredigits and initialize its value to 0.
sumsquaredigits = 0
# Loop in this digits list using For loop.
for digitvalu in numbrlistdigits:
# Increment the value of sumsquaredigits by the square
# of the digit(iterator value).
sumsquaredigits = sumsquaredigits+(digitvalu**2)
# Return the sumsquaredigits value
return sumsquaredigits

# Create a function checkhapppynumb() which accepts the number as an argument
# and returns true if it is happy number else returns False.

def checkhapppynumb(numb):
# Take a variable rest and initialize its value to the given argument.
rest = numb
# Loop till the rest is not equal to 1 or 4 using while loop.
while(rest != 1 and rest != 4):
# Inside the loop pass the reslt value to digitSquareSum()
# and store it in the same variable reslt.
rest = digitSquareSum(rest)
# After the end of the while loop,
# Check whether rest value is 1 or not using the If statement.
if(rest == 1):
# If it is true then the given number is a happy number so return True
return True
else:
# Else it is not a happy number so return False.
return False

# Give the lower limit range and upper limit range as
# user input using map(),int(),split() functions.
# Store them in two separate variables.
lowlimrange, upplimrange = map(int, input(
'Enter lower limit range and upper limit range separate bt spaces = ').split())
print('The Harshad numbers in the given range',
lowlimrange, 'and', upplimrange, 'are:')
print('The happy numbers in the given range',
lowlimrange, 'and', upplimrange, 'are:')
# Loop from lower limit range to upper limit range using For loop.
for l in range(lowlimrange, upplimrange+1):
# IInside the for loop pass the iterator value to checkhapppynumb() function.
if(checkhapppynumb(l)):
# If it returns true then print the iterator value.
print(l, end=' ')


Output:

Enter lower limit range and upper limit range separate bt spaces = 333 444
The Harshad numbers in the given range 333 and 444 are:
The happy numbers in the given range 333 and 444 are:
338 356 362 365 367 368 376 379 383 386 391 392 397 404 409 440

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