fruits = ['apple', 'banana', 'cherry']
for fruit in fruits:
    print(fruit)

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

# 使用生成器
for num in fibonacci():
    if num > 100:
        break
    print(num)

class SimpleIterator:
    def __init__(self, limit):
        self.limit = limit
        self.current = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self.current >= self.limit:
            raise StopIteration
        value = self.current
        self.current += 1
        return value

# 使用迭代器
it = SimpleIterator(5)
for i in it:
    print(i)

my_list = [1, 2, 3]
my_iterator = iter(my_list)

print(next(my_iterator))  # 輸出: 1
print(next(my_iterator))  # 輸出: 2
print(next(my_iterator))  # 輸出: 3

for i in range(5):
    print(i)  # 輸出: 0, 1, 2, 3, 4

class NumberSequenceIterator:
    def __init__(self, start, end):
        self.current = start
        self.end = end

    def __iter__(self):
        return self

    def __next__(self):
        if self.current > self.end:
            raise StopIteration
        result = self.current
        self.current += 1
        return result

# 使用自定義迭代器
seq_iter = NumberSequenceIterator(1, 5)
for num in seq_iter:
    print(num)

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

# 使用生成器
for num in fibonacci():
    if num > 100:
        break
    print(num)

squares = (x**2 for x in range(10))
for square in squares:
    print(square)

class FibonacciIterator:
    def __init__(self, max_num):
        self.max_num = max_num
        self.a, self.b = 0, 1

    def __iter__(self):
        return self

    def __next__(self):
        if self.a > self.max_num:
            raise StopIteration
        result = self.a
        self.a, self.b = self.b, self.a + self.b
        return result

# 使用自定義迭代器
fib_iter = FibonacciIterator(100)
for num in fib_iter:
    print(num)

import random

def infinite_randoms():
    while True:
        yield random.random()

# 使用無限隨機數(shù)迭代器
for _ in range(10):
    print(next(infinite_randoms()))

# 無法反向迭代
my_list = [1, 2, 3]
my_iter = iter(my_list)
for _ in my_iter:
    pass  # 消耗完迭代器
try:
    next(my_iter)
except StopIteration:
    print("迭代器已耗盡，無法回溯")

# 列表推導式
large_list = [i for i in range(1000000)]
# 迭代器
large_iter = (i for i in range(1000000))

# 比較內(nèi)存占用
import sys
print(sys.getsizeof(large_list))  # 輸出：較大的內(nèi)存占用
print(sys.getsizeof(large_iter))  # 輸出：較小的內(nèi)存占用

fruits = ['apple', 'banana', 'cherry']
for index, fruit in enumerate(fruits):
    print(f"Index: {index}, Fruit: {fruit}")

names = ['Alice', 'Bob', 'Charlie']
ages = [25, 30, 35]
for name, age in zip(names, ages):
    print(f"{name} is {age} years old.")

from itertools import count

for num in count(10, step=2):
    if num > 20:
        break
    print(num)

my_list = [1, 2, 3, 4, 5]
for item in reversed(my_list):
    print(item)

numbers = [1, 2, 3, 4, 5, 6]
even_numbers = filter(lambda x: x % 2 == 0, numbers)
for num in even_numbers:
    print(num)

squared = map(lambda x: x ** 2, numbers)
for square in squared:
    print(square)

with open('example.txt', 'r') as file:
    for line in file:
        print(line.strip())  # 去除每行末尾的換行符

import pandas as pd

df = pd.read_csv('data.csv')
def clean_data(value):
    # 清洗邏輯
    return cleaned_value

for index, row in df.iterrows():
    row['column_name'] = clean_data(row['column_name'])
    # 保存或更新數(shù)據(jù)

import threading

tasks = [{'id': 1, 'work': 'Task 1'}, {'id': 2, 'work': 'Task 2'}, ...]

def worker(task):
    print(f"Worker: {threading.current_thread().name} doing task {task['id']}")

threads = []
for task in tasks:
    t = threading.Thread(target=worker, args=(task,))
    threads.append(t)
    t.start()

# 等待所有線程完成
for t in threads:
    t.join()

import requests
from bs4 import BeautifulSoup

def crawl(url):
    response = requests.get(url)
    soup = BeautifulSoup(response.text, 'html.parser')
    links = soup.find_all('a')
    for link in links:
        print(link.get('href'))

# 調(diào)用爬蟲函數(shù)
crawl('https://example.com')

my_list = [1, 2, 3]
iter1 = iter(my_list)
for i in iter1:
    print(i)  # 輸出: 1, 2, 3
for i in iter1:  # 這次不會輸出任何內(nèi)容，因為iter1已經(jīng)遍歷完畢
    print(i)

my_iter = iter([1, 2, 3])
try:
    while True:
        print(next(my_iter))
except StopIteration:
    print("迭代器已耗盡")

# 不可逆的迭代器
my_iter = iter([1, 2, 3])
# 無法反向迭代
for i in reversed(my_iter):  # 報錯: TypeError: 'iterator' object is not reversible
    print(i)

# 可反向迭代的列表
my_list = [1, 2, 3]
for i in reversed(my_list):
    print(i)

import threading

def worker(iterable, lock):
    with lock:
        for item in iterable:
            print(f"Thread {threading.current_thread().name}: {item}")

my_list = [1, 2, 3]
lock = threading.Lock()
threads = []

for _ in range(3):
    t = threading.Thread(target=worker, args=(my_list, lock))
    threads.append(t)
    t.start()

# 等待所有線程完成
for t in threads:
    t.join()

import asyncio

async def async_generator():
    for i in range(5):
        await asyncio.sleep(1)
        yield i

async def main():
    async for i in async_generator():
        print(f"Generated: {i}")

# 運行異步主函數(shù)
asyncio.run(main())