file = open(filename, mode)

# 定義文件名
filename = "log.txt"

# 使用 'a' 模式打開文件并追加內(nèi)容
with open(filename, 'a', encoding='utf-8') as f:
    f.write("【2024-05-20】系統(tǒng)啟動成功 ??\n")
    f.write("CPU占用率：37% ??\n")
    f.write("內(nèi)存使用：4.2GB / 16GB ??\n")

print("? 日志已成功追加到文件中！")

entries = [
    "【2024-05-20】用戶登錄成功 ??",
    "設備型號：iPhone 15 Pro ??",
    "IP地址：192.168.1.100 ??"
]

with open("user_log.txt", 'a', encoding='utf-8') as f:
    for entry in entries:
        f.write(entry + "\n")  # 手動添加換行

# 錯誤：沒有換行，所有內(nèi)容擠在一行
for entry in entries:
    f.write(entry)  # 缺少 \n

import datetime

def log_system_status():
    timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    status_info = [
        f"【{timestamp}】系統(tǒng)健康檢查完成 ?",
        f"服務運行正常：?",
        f"數(shù)據(jù)庫連接：?",
        f"緩存命中率：92% ??",
        f"當前在線用戶數(shù)：1,243 ??"
    ]

    with open("system.log", 'a', encoding='utf-8') as log_file:
        for line in status_info:
            log_file.write(line + "\n")
    
    print(f"?? 日志已追加：{timestamp}")

# 模擬每小時調(diào)用一次
log_system_status()

【2024-05-20 14:30:22】系統(tǒng)健康檢查完成 ?
服務運行正常：?
數(shù)據(jù)庫連接：?
緩存命中率：92% ??
當前在線用戶數(shù)：1,243 ??

# 模擬用戶行為數(shù)據(jù)
user_actions = [
    {"user": "Alice", "action": "login", "time": "2024-05-20 10:15"},
    {"user": "Bob", "action": "purchase", "time": "2024-05-20 10:16"},
    {"user": "Charlie", "action": "view_product", "time": "2024-05-20 10:17"}
]

# 追加到日志文件
with open("user_activity.log", 'a', encoding='utf-8') as f:
    for record in user_actions:
        line = f"[{record['time']}] {record['user']} -> {record['action']}"
        f.write(line + "\n")

print("?? 用戶行為日志已成功追加！")

def safe_append_to_file(filename, content):
    try:
        with open(filename, 'a', encoding='utf-8') as f:
            f.write(content + "\n")
        print(f"? 成功追加內(nèi)容到 {filename}")
        return True
    except PermissionError:
        print("? 權限不足，無法寫入文件！請檢查文件權限。")
        return False
    except OSError as e:
        print(f"? 文件系統(tǒng)錯誤：{e}")
        return False
    except Exception as e:
        print(f"? 未知錯誤：{e}")
        return False

# 測試
safe_append_to_file("debug.log", "【DEBUG】程序初始化完成")

# 不推薦：逐行寫入
with open("large_log.txt", 'a', encoding='utf-8') as f:
    for i in range(100000):
        f.write(f"日志條目 {i}\n")

# 推薦：先收集再一次性寫入
lines = []
for i in range(100000):
    lines.append(f"日志條目 {i}")

with open("large_log.txt", 'a', encoding='utf-8') as f:
    f.writelines(lines)  # 更高效

import threading

lock = threading.Lock()
log_filename = "concurrent_log.txt"

def write_safe_log(message):
    with lock:  # 確保同一時間只有一個線程寫入
        with open(log_filename, 'a', encoding='utf-8') as f:
            f.write(message + "\n")

# 模擬多個線程同時寫入
threads = []
for i in range(5):
    t = threading.Thread(target=write_safe_log, args=(f"線程{i} 寫入數(shù)據(jù) {i}",))
    threads.append(t)
    t.start()

for t in threads:
    t.join()

print("? 多線程追加完成，數(shù)據(jù)無沖突！")

with open("test.txt", 'a', encoding='utf-8') as f:
    f.write("?? 第一次追加成功！\n")
    f.write("?? 進階之路，從這里開始！\n")