python tutorial - Python Fibonacci Series program - learn python - python programming




Fibonacci Series

  • In Mathematics, Fibonacci Series or Fibonacci Numbers are the numbers that are displayed in following sequence.
  • Fibonacci Series = 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 …
  • If you observe the above pattern, First Value is 0, Second Value is 1 and the subsequent number is the result of sum of the previous two numbers. For example, Third value is (0 + 1), Fourth value is (1 + 1) so on and so forth.
  • In this article we will show you, How to Write Python Fibonacci Series program using While Loop, For Loop and Recursion.
 Python Fibonacci Series program

Learn Python - Python tutorial - Python Fibonacci Series program - Python examples - Python programs

Python Fibonacci Series program Using While Loop

  • This Python program allows the user to enter any positive integer and then, this program will display the fibonacci series of number from 0 to user specified number using the Python While Loop

Sample Code

# Python Fibonacci series Program using While Loop
 
# Fibonacci series will start at 0 and travel upto below number
Number = int(input("\nPlease Enter the Range Number: "))
 
# Initializing First and Second Values of a Series
i = 0
First_Value = 0
Second_Value = 1
           
# Find & Displaying Fibonacci series
while(i < Number):
           if(i <= 1):
                      Next = i
           else:
                      Next = First_Value + Second_Value
                      First_Value = Second_Value
                      Second_Value = Next
           print(Next)
           i = i + 1
click below button to copy the code. By Python tutorial team

OUTPUT

 Python Fibonacci Series program Using While Loop

Learn Python - Python tutorial - Python Fibonacci Series program Using While Loop - Python examples - Python programs

ANALYSIS

  • This program allows the user to enter any positive integer and then, that number is assigned to variable Number. Next, We declared three integer variables i, First_Value and Second_Value and assigned values as we shown above. Below While loop will make sure that, the loop will start from 0 and it is less than the user given number. Within the While loop, we used If statement.
    • If i value is less than or equal to 1 then, Next will be i
    • If i value is greater than 1, perform calculations inside the Else block.
while(i < Number):
           if(i <= 1):
                      Next = i
           else:
                      Next = First_Value + Second_Value
                      First_Value = Second_Value
                      Second_Value = Next
           print(Next)
           i = i + 1
click below button to copy the code. By Python tutorial team
  • Let us see the working principle of this while loop in iteration wise.
  • User Entered value: Number = 4 and i = 0, First_Value = 0, Second_Value = 1

First Iteration

  • While (0 < 4) is TRUE so, program will start executing statements inside the while loop
  • Within the while loop we have If statement and the condition if (0 <= 1) is TRUE so Next = 0 and compiler will exit from if statement block
  • Print statement print(Next) will print the value 0
  • Lastly, i will be incremented to 1

Second Iteration

  • While (1 < 4) is TRUE so, program will start executing statements inside the while loop
  • Within the while loop we have If statement and the condition if (1 <= 1) is TRUE so Next = 1 and compiler will exit from if statement block
  • Print statement print(Next) will print the value 1
  • Lastly, i will be incremented to 1

Third Iteration

  • While (2 < 4) is TRUE so, program will start executing statements inside the while loop. Within the while loop we have If statement and the condition if (2 <= 1) is FALSE so statements inside the else block will start executing
    • Next = First_Value + Second_Value
    • Next = 0 + 1 = 1
    • First_Value = Second_Value = 1
    • Second_Value = Next = 1
  • Next, Print statement print(Next) will print the value 1. Lastly, i will be incremented to 1

Fourth Iteration

  • While (3 < 4) is TRUE so, program will start executing statements inside the while loop. Within the while loop we have If statement and the condition if (3 <= 1) is FALSE so statements inside the else block will start executing
    • Next = First_Value + Second_Value
    • Next = 1 + 1 = 2
    • First_Value = Second_Value = 1
    • Second_Value = Next = 2
  • Next, Print statement print(Next) will print the value 2. Lastly, i will be incremented to 1

Fifth Iteration

  • While (4 < 4) is FALSE so, program will exit from the while loop.
  • From the above, Our final output of Next values are: 0 1 1 2

Python Fibonacci Series program Using For Loop

  • This Python program allows the user to enter any positive integer and then, this program will display the fibonacci series of number from 0 to user specified number using Python For Loop

Sample Code

# Python Fibonacci series Program using For Loop
 
# Fibonacci series will start at 0 and travel upto below number
Number = int(input("\nPlease Enter the Range Number: "))
 
# Initializing First and Second Values of a Series
First_Value = 0
Second_Value = 1
           
# Find & Displaying Fibonacci series
for Num in range(0, Number):
           if(Num <= 1):
                      Next = Num
           else:
                      Next = First_Value + Second_Value
                      First_Value = Second_Value
                      Second_Value = Next
           print(Next)
click below button to copy the code. By Python tutorial team

OUTPUT

 Python Fibonacci Series program Using For Loop

Learn Python - Python tutorial - Python Fibonacci Series program Using For Loop - Python examples - Python programs

  • We just replaced the While loop in the above example with the For loop. If you don’t understand the for loop then please refer For Loop article here: Python For Loop

Python Fibonacci Series program Using Recursion

  • This Python program allows the user to enter any positive integer and then, this program will display the fibonacci series of number from 0 to user specified number using Recursion concept.

Sample Code

# Python Fibonacci series Program using Recursion
 
# Recursive Function Beginning
def Fibonacci_series(Number):
           if(Number == 0):
                      return 0
           elif(Number == 1):
                      return 1
           else:
                      return (Fibonacci_series(Number - 2)+ Fibonacci_series(Number - 1))
 
# End of the Function
 
# Fibonacci series will start at 0 and travel upto below number
Number = int(input("\nPlease Enter the Range Number: "))
 
# Find & Displaying Fibonacci series
for Num in range(0, Number):
           print(Fibonacci_series(Num))
click below button to copy the code. By Python tutorial team

OUTPUT

 Python Fibonacci Series program Using Recursion

Learn Python - Python tutorial - Python Fibonacci Series program Using Recursion - Python examples - Python programs

ANALYSIS

  • In this example we defined a function. Following function will accept integer values as parameter value and return value

def Fibonacci_series(Number):
click below button to copy the code. By Python tutorial team
    • if (Number == 0) will check whether the given number is 0 or not. If it is TRUE, function will return the value Zero.
    • if (Number == 1) will check whether the given number is 1 or not. If it is TRUE, function will return the value One.
    • If the number is greater than 1 then the statements inside the else block will be executed.
  • Within the Else block we called the function recursively to display the Fibonacci series.
return (Fibonacci_series(Number - 2)+ Fibonacci_series(Number - 1))
click below button to copy the code. By Python tutorial team

For example, Number = 2
(Fibonacci_series(Number – 2)+ Fibonacci_series(Number – 1))
(Fibonacci_series(2 – 2)+ Fibonacci_series(2 – 1)), It means
(Fibonacci_series(0)+ Fibonacci_series(1))
return (0 + 1) = return 1

  • NOTE: For Recursive functions it is very important to place a condition before using the function recursively otherwise, we will end up in infinite execution (Same like infinite Loop).

Related Searches to Python Fibonacci Series program

Adblocker detected! Please consider reading this notice.

We've detected that you are using AdBlock Plus or some other adblocking software which is preventing the page from fully loading.

We don't have any banner, Flash, animation, obnoxious sound, or popup ad. We do not implement these annoying types of ads!

We need money to operate the site, and almost all of it comes from our online advertising.

Please add wikitechy.com to your ad blocking whitelist or disable your adblocking software.

×