file = open('example.txt', 'r')
content = file.read()  # 讀取整個文件內(nèi)容
file.close()

file = open('example.txt', 'r')
line = file.readline()  # 讀取第一行
file.close()

file = open('example.txt', 'r')
lines = file.readlines()  # 獲取包含所有行的列表
file.close()

# 分塊讀取大文件
def read_in_chunks(file_path, chunk_size=1024):
    with open(file_path, 'r') as file:
        while True:
            chunk = file.read(chunk_size)
            if not chunk:
                break
            yield chunk

# 使用生成器逐塊處理大文件
for chunk in read_in_chunks('large_file.txt'):
    process(chunk)  # 處理每個塊

# 使用readline()遍歷文件
with open('example.txt', 'r') as file:
    while True:
        line = file.readline()
        if not line:  # 到達文件末尾
            break
        print(line, end='')  # 去除print自帶的換行

# 更Pythonic的方式是直接迭代文件對象
with open('example.txt', 'r') as file:
    for line in file:
        print(line, end='')

# 使用列表推導(dǎo)式處理所有行
with open('example.txt', 'r') as file:
    lines = [line.strip() for line in file.readlines()]
    # 或者更高效的寫法
    lines = [line.strip() for line in file]  # 直接迭代文件對象

# 隨機訪問文件行
with open('example.txt', 'r') as file:
    lines = file.readlines()
    print(lines[10])  # 訪問第11行
    print(lines[-1])  # 訪問最后一行

import time

def test_read(filename):
    start = time.time()
    with open(filename, 'r') as file:
        content = file.read()
    return time.time() - start

def test_readline(filename):
    start = time.time()
    with open(filename, 'r') as file:
        while file.readline():
            pass
    return time.time() - start

def test_readlines(filename):
    start = time.time()
    with open(filename, 'r') as file:
        lines = file.readlines()
    return time.time() - start

def test_iter(filename):
    start = time.time()
    with open(filename, 'r') as file:
        for line in file:
            pass
    return time.time() - start

filename = 'large_file.txt'  # 假設(shè)這是一個100MB的文件

print(f"read() time: {test_read(filename):.4f} seconds")
print(f"readline() time: {test_readline(filename):.4f} seconds")
print(f"readlines() time: {test_readlines(filename):.4f} seconds")
print(f"file iteration time: {test_iter(filename):.4f} seconds")

read() time: 0.1254 seconds
readline() time: 0.2345 seconds
readlines() time: 0.1321 seconds
file iteration time: 0.1208 seconds

def tail(filename, n=10):
    with open(filename, 'rb') as file:
        # 移動到文件末尾前1024字節(jié)
        file.seek(-1024, 2)
        lines = file.readlines()
        return [line.decode() for line in lines[-n:]]

with open('example.txt', 'r', encoding='utf-8') as file:
    content = file.read()