[Python] Happy numbers

If we take a number, and sum the square of its digits, and then continue this process with the new number, we will either arrive at 1, or we will loop endlessly in a cycle that repeats itself. Those numbers that eventually end up at 1 are called happy numbers.

Consider the number 19. If we square its digits and then add them together, we get:

1² + 9² = 82

Then again:

8² + 2² = 68

Continuing in this fashion, we get:

6² + 8² = 100

And Finally:

1² + 0² + 0² = 1.

Therefore we can say that 19 is a happy number. Now you know who you are inviting for your next party.

So, we want to write a function to check for happy numbers. Here is what the function will do in a nutshell:

Receive a number and turn it into string
Sum the square of the digits of the number
If the resulting number is equal to 1, then it is a happy number.
Else if we have not seen the result before (no cycle has formed) continue the process
If a cycle is detected, then break the loop. The number is a sad number.

"""Econowmics.com"""

#Happy numbers
def happy(n):
"""The function receives a number and returns TRUE if it is a happy number."""

    #Turning the number to string
    number = str(n)

    #container
    container = []

    #running a for loop to square each digit
    while True:
    #temporary variable, need to be set zero in each loop
    temp = 0
    #add each digit squared to the 'temp' variable
    for digit in number:
        temp += int(digit) ** 2

    #After the loop for all digits has ended, now is temp equal to 1? (is it a happy number?)
    if temp == 1:
        return True
        break
    #Or, has this number ever occured before? if so, then it is a sad number
    elif temp in container:
        return False
        break
    #otherwise, just add it to the container and set the starting number equal to the value of temp
    else:
        container.append(temp)
        number = str(temp)

Let us run a quick test to see how much it takes for the function to calculate how many happy numbers are therebelow 1000:

#Importing the time module
import time

#Marking the start of time
start= time.time()

#Variable to store the number of happy numbers
count = 0

#Loop to check for happy numbers
for i in range(1,1001):
    if happy(i):
        count += 1

#Marking the end of time
end = time.time()

#Printing the output to the console
print ('Total happy numbers below 1000: ' + str(count))
print ('It took: ' + str(end-start))

Here is the result:

Happy numbers - result

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