How to compute all the factors of a given number in Python

The following python program computes and prints all the positive factors of a given input number.

Code

# This function returns a list containing all the factors of a ginven parameters n
def getFactors(n):
    # Create an empty list for factors
    factors=[];

    # Loop over all factors
    for i in range(1, n + 1):
        if n % i == 0:
            factors.append(i)

    # Return the list of factors
    return factors

# Call the function with a given value
print (getFactors(256))

Here is how the above program works:

• we define a function getFactors() which takes a number as input and returns a list of factors;
• this function initially creates an empty list;
• the function then iterates through number 1 to n using the built-in function range();
• if the reminder is 0, we know that the number is a factor of input number and hence we add it to the factors list;
• finally the factors list is returned.

Output

[1, 2, 4, 8, 16, 32, 64, 128, 256]

Prime number

It becomes easy to test if a given integer is a prime number:

if len(getFactors(42))==2:
    print ('Prime number')
else:
    print ('Not a prime number')

See also

• Copy lists in Python
• Count list elements in Python
• Create lists in Python
• DataFrames in Pandas/Python
• Delete lists in Python
• Get list elements in Python
• How to get and parse HTML pages in Python?
• Insert, append, extend and concatanate lists in Python
• Install Visual Studio Code on Ubuntu for Python
• Iterate over lists in Python
• Matplotlib and Visual Studio Code
• Remove an element from a list in Python
• Reverse lists in Python
• Find elements in lists in Python
• Slice lists in Python

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