Yield and generators

import time

start = time.time()
def even_numbers(n):
    for i in range(0, n+1, 2):
        yield i

numbers = even_numbers(10_000_000)
evens = []
for number in numbers:  
    evens.append(number)
end = time.time()
print(end-start)



start2 = time.time()
evens2 =[]
for n in range(10_000_000):
    if n%2 ==0:
        evens2.append(n)

end2 = time.time()
print(end2-start2)


# 0.8700542449951172
# 1.6380994319915771

Efficiency Analysis

• Generator Function (Method 1): This method is more efficient, taking about 0.87 seconds to complete.
• Direct Loop (Method 2): This method is less efficient, taking about 1.64 seconds to complete.

Reasons for Efficiency Difference

Iteration Range:

• Method 1 iterates only over even numbers (0, 2, 4, …, 10,000,000).
• Method 2 iterates over all numbers from 0 to 9,999,999. Condition Checking:
• Method 1 doesn’t need to check if a number is even; it generates only even numbers.
• Method 2 checks every number with the condition n//2 ==0, which is actually incorrect (should be n % 2 == 0). Memory Usage:
• Method 1 uses a generator, which yields values one at a time, saving memory.
• Method 2 creates the entire range in memory before iterating.

Number of Operations:

• Method 1 performs fewer operations overall, as it only deals with even numbers.
• Method 2 performs more operations, checking every number and doing an integer division for each.

Most efficient method

start3 = time.time()
evens3 = list(range(0, 10_000_000, 2))
end3 = time.time()
print(end3-start3)

# 0.2165060043334961