Python readlines()方法 - 一次性读取文件所有行

# 文件读取readlines相关语法示例
file.readlines(hint)
# hint: 可选参数，指定读取的行数
# 返回值：包含所有行的列表，每行包含换行符

# 基本用法示例
# 读取所有行
with open("example.txt", "r", encoding="utf-8") as file:
    lines = file.readlines()
    for line in lines:
        print(line.strip())

# 读取前3行
with open("example.txt", "r", encoding="utf-8") as file:
    lines = file.readlines(3)
    for line in lines:
        print(line.strip())

# 详细代码示例
# 示例1：读取所有行并处理
with open("data.txt", "r", encoding="utf-8") as file:
    lines = file.readlines()
    print(f"文件共有 {len(lines)} 行")
    for i, line in enumerate(lines, 1):
        print(f"第{i}行: {line.strip()}")

# 示例2：读取并过滤空行
with open("data.txt", "r", encoding="utf-8") as file:
    lines = file.readlines()
    non_empty_lines = [line.strip() for line in lines if line.strip()]
    print(f"非空行数: {len(non_empty_lines)}")

# 示例3：读取特定行数
def read_first_n_lines(filename, n):
    with open(filename, "r", encoding="utf-8") as file:
        return file.readlines(n)

first_5_lines = read_first_n_lines("data.txt", 5)
for line in first_5_lines:
    print(line.strip())