全角半角转换

对于小文件：

# -*- coding: utf-8 -*-

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('-m', '--mode', default='f2h', help='full2half or half2full')
parser.add_argument('-i', '--input_file', help='input filename')
parser.add_argument('-o', '--output_file', default='output.txt', help='output filename')

args = parser.parse_args()

# 全角对应半角字典
# ASCII字符
full_to_half = {chr(i): chr(i - 0xfee0) for i in range(0xFF01, 0xFF5E + 1)}
full_to_half[chr(0x3000)] = chr(0x20)

# 半角对应全角字典
half_to_full = dict((v, k) for k, v in full_to_half.items())


def full2half(text):
    """全角转半角
    :param text: 输入文本
    :return: 输出文本
    """
    return ''.join([full_to_half.get(i, i) for i in text])


def half2full(text):
    """半角转全角
    :param text: 输入文本
    :return: 输出文本
    """
    return ''.join([half_to_full.get(i, i) for i in text])


def main():
    with open(args.input_file, 'r', encoding='utf-8') as f_in, 
            open(args.output_file, 'w', encoding='utf-8') as f_out:
        text = f_in.read()
        if args.mode == 'f2h':
            output_text = full2half(text)
        else:
            output_text = half2full(text)
        f_out.write(output_text)


if __name__ == '__main__':
    main()

对于大文件：

# -*- coding: utf-8 -*-

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('-m', '--mode', default='f2h', help='full2half or half2full')
parser.add_argument('-i', '--input_file', help='input filename')
parser.add_argument('-o', '--output_file', default='output.txt', help='output filename')

args = parser.parse_args()

# 全角对应半角字典
# ASCII字符
full_to_half = {chr(i): chr(i - 0xfee0) for i in range(0xFF01, 0xFF5E + 1)}
full_to_half[chr(0x3000)] = chr(0x20)

# 半角对应全角字典
half_to_full = dict((v, k) for k, v in full_to_half.items())


def full2half(text):
    """全角转半角
    :param text: 输入文本
    :return: 输出文本
    """
    return ''.join([full_to_half.get(i, i) for i in text])


def half2full(text):
    """半角转全角
    :param text: 输入文本
    :return: 输出文本
    """
    return ''.join([half_to_full.get(i, i) for i in text])


def main():
    with open(args.input_file, 'r', encoding='utf-8') as f_in, 
            open(args.output_file, 'w', encoding='utf-8') as f_out:
        for text in f_in:
            if args.mode == 'f2h':
                output_text = full2half(text)
            else:
                output_text = half2full(text)
            f_out.write(output_text)


if __name__ == '__main__':
    main()