Python 小项目练习(1)

batch_file_rename.py

__author__ = 'Craig Richards'
__version__ = '1.0'

import argparse
import os

# 批量重命名  # 工作目录, 旧文件, 新文件
def batch_rename(work_dir, old_ext, new_ext):
    """
    tHIS will batch rename a group of files in a given directory,
    once you pass the current and new extensions
    """
    # files: 以列表的形式 列出工作目录的文件  ['0.txt', '2.txt', 'batch_file_rename.py']
    # files = os.listdir(work_dir)
    # 遍历工作目录的文件
    for filename in os.listdir(work_dir):
        # Get the file extension
        # 分离文件名和扩展名 得到元组
        # ('0', '.txt')
        # ('2', '.txt')
        # ('batch_file_rename', '.py')
        split_file = os.path.splitext(filename)
        # Unpack tuple element
        # 将元组各值赋值给两个变量
        # 文件名, 文件格式
        root_name, file_ext = split_file
        # Start of the logic to check the file extensions, if old_ext = file_ext
        # 如果当前文件的格式等于旧文件的格式
        if old_ext == file_ext:
            # Returns changed name of the file with new extention
            # 拼接新文件名
            newfile = root_name + new_ext

            # Write the files
            # 重命名文件 ( 1.原文件名  2.新文件名 )
            os.rename(
                # 拼接路径和文件名
                os.path.join(work_dir, filename),
                os.path.join(work_dir, newfile)
            )
    print("rename is done!")
    print(os.listdir(work_dir))


# 获取解析
def get_parser():
    # 使用argparse方法的ArgumentParser生成实例
    # 更改工作目录中文件的扩展名
    parser = argparse.ArgumentParser(description='change extension of files in a working directory')

    # 工作目录 , 元变量
    parser.add_argument('work_dir', metavar='WORK_DIR', type=str, nargs=1,
                        help='the directory where to change extension')
    parser.add_argument('old_ext', metavar='OLD_EXT', type=str, nargs=1, help='old extension')
    parser.add_argument('new_ext', metavar='NEW_EXT', type=str, nargs=1, help='new extension')
    return parser


def main():
    """
    This will be called if the script is directly invoked.
    :return:
    """
    # 增加命令行参数
    # 将get_parser()获取的值存入parser中
    parser = get_parser()
    # vars()函数返回对象object的属性和属性值的字典对象
    args = vars(parser.parse_args())

    # Set the variable work_dir with the first argument passed
    # 设置变量work_dir 并传递第一个参数
    work_dir = args['work_dir'][0]
    # Set the variable old_ext with the second argument passed
    # 设置变量old_ext 并传递第二个参数
    old_ext = args['old_ext'][0]

    # 如果old_ext的第一个参数不是'.'
    if old_ext[0] != '.':
        # 给old_ext的前面加个'.'
        old_ext = '.' + old_ext
    # Set the variable new_ext with the third argument passed
    new_ext = args['new_ext'][0]
    if new_ext[0] != '.':
        new_ext = '.' + new_ext

    batch_rename(work_dir, old_ext, new_ext)
if __name__ == '__main__':
    main()

create_dir_if_not_there.py

import os

MESSAGE = 'The directory already exists.'
TESTDIR = 'testdir'
try:
    # 扩展用户设置的主目录  # C:\Users\PC1
    home = os.path.expanduser("~") # Set the variable home by expanding  the user's set home directory
    print(home) # Print the location
    # 如果不存在
    if not os.path.exists(os.path.join(home, TESTDIR)):
        # 安全的创建一个全路径(安全拼接home路径和文件名)
        os.makedirs(os.path.join(home, TESTDIR)) # If not create the directory, inside their home directory
    else:
        print(MESSAGE)
except Exception as e:
    print(e)