Implementing A Fibonacci Number Generator¶
Fibonacci Numbers: Naive List¶
#!/usr/bin/python
def fibonacci():
fibo_numbers = []
previous = 1
current = 1
while True:
next = previous + current
fibo_numbers.append(next)
previous, current = current, next
return fibo_numbers
if __name__ == '__main__':
for num in fibonacci():
print(num)
watch OS become overly jerky, until process is OOM-killed
well, there’s need for a limit
Fibonacci Numbers: Naive List, Limited¶
#!/usr/bin/python
def fibonacci(max_numbers=100):
fibo_numbers = []
previous = 1
current = 1
while len(fibo_numbers) < max_numbers:
next = previous + current
fibo_numbers.append(next)
previous, current = current, next
return fibo_numbers
if __name__ == '__main__':
for num in fibonacci():
print(num)
Sideway: Infinity by Not Using Functions¶
Still not satisfactory
Want infinity
Can be done, by embedding the using code (
print()) into the Fibonacci generation.not so modular though
#!/usr/bin/python
previous = 1
current = 1
while True:
next = previous + current
print(next)
previous, current = current, next
Fibonacci Numbers: Function Producing Infinite Sequence¶
#!/usr/bin/python
def fibonacci():
previous = 1
current = 1
while True:
next = previous + current
yield next
previous, current = current, next
if __name__ == '__main__':
for num in fibonacci():
print(num)
Common Pattern: Turn List into Generated Items¶
correct infinity can save a few lines
--- /home/jfasch/My-Projects/jfasch-home/trainings/material/soup/python/advanced/iteration-generation/python_1010_generators_yield/code/10-fibo-list-nolimit.py
+++ /home/jfasch/My-Projects/jfasch-home/trainings/material/soup/python/advanced/iteration-generation/python_1010_generators_yield/code/40-fibo-generator.py
@@ -1,16 +1,12 @@
#!/usr/bin/python
def fibonacci():
- fibo_numbers = []
-
previous = 1
current = 1
while True:
next = previous + current
- fibo_numbers.append(next)
+ yield next
previous, current = current, next
-
- return fibo_numbers
if __name__ == '__main__':
for num in fibonacci():