Python3实现全角与半角字符互转的完整指南

沿途有光

发布时间：2026-10-13| 4人浏览过

原创

本文详细解析Python3中全角（DBC）与半角（SBC）字符的转换原理及实现方法。通过解析字符编码差异，提供完整的转换函数代码，涵盖数字、字母及常见标点符号的互转逻辑，并特别指出中文及特殊符号的处理边界，适用于学生答题数据清洗等场景。

前言

本文主要介绍Python3环境下全角与半角字符转换的相关技术细节，旨在为开发者提供实用的参考方案。接下来将深入探讨具体的实现逻辑与应用场景。

一、背景介绍

核心目标：实现文本中全角与半角字符的快速、自动转换。

典型应用场景：例如在学生答题数据预处理中，将用户输入的全角字符统一替换为半角字符，以规范数据格式。

二、全角半角转换原理

全角字符（Double Byte Character，简称DBC）通常占用两个字节。

半角字符（Single Byte Character，简称SBC）通常占用一个字节。

在Windows系统编码中，中文及全角字符均占用两个字节，且其编码范围涉及ASCII Chart 2（即代码128–255区间）。具体而言，全角字符的第一个字节固定为163，而第二个字节等于对应半角字符的码值加上128。需要注意的是，空格的处理较为特殊，全角空格与半角空格的转换逻辑需单独考量。

对于中文字符，其第一个字节通常大于163（例如汉字“阿”的编码为176和162）。在转换算法中，检测到此类字符时应跳过转换，保持原样。

具体示例：半角字母“a”的ASCII码为65，转换为全角后，其第一个字节为163，第二个字节为193（即128 + 65）。

全角与半角转换效果示例：参考文件test.txt，其中包含混合的全角和半角字符数据。

F:\test>type test.txt
123456
１２３４５６
abcdefg
ａｂｃｄｅｆｇ
中国你好

三、使用 Python3 实现全角半角转换

# -*- coding:utf-8 -*-
# i@mail.chenpeng.info

”'
全角即：Double Byte Character，简称：DBC
半角即：Single Byte Character，简称：SBC
”'

def DBC2SBC(ustring):
 ”' 全角转半角 ”'
 rstring = “”
 for uchar in ustring:
  inside_code = ord(uchar)
  if inside_code == 0x3000:
  inside_code = 0x0020
  else:
  inside_code -= 0xfee0
  if not (0x0021 <= inside_code and inside_code <= 0x7e):
   rstring += uchar
   continue
  rstring += chr(inside_code)
 return rstring

def SBC2DBC(ustring):
 ”' 半角转全角 ”'
 rstring = “”
 for uchar in ustring:
  inside_code = ord(uchar)
  if inside_code == 0x0020:
  inside_code = 0x3000
  else:
  if not (0x0021 <= inside_code and inside_code <= 0x7e):
   rstring += uchar
   continue
  inside_code += 0xfee0
  rstring += chr(inside_code)
 return rstring

s = ”'
array(‘０' => ‘0', ‘１' => ‘1', ‘２' => ‘2', ‘３' => ‘3', ‘４' => ‘4',
  ‘５' => ‘5', ‘６' => ‘6', ‘７' => ‘7', ‘８' => ‘8', ‘９' => ‘9',
  ‘Ａ' => ‘A', ‘Ｂ' => ‘B', ‘Ｃ' => ‘C', ‘Ｄ' => ‘D', ‘Ｅ' => ‘E',
  ‘Ｆ' => ‘F', ‘Ｇ' => ‘G', ‘Ｈ' => ‘H', ‘Ｉ' => ‘I', ‘Ｊ' => ‘J',
  ‘Ｋ' => ‘K', ‘Ｌ' => ‘L', ‘Ｍ' => ‘M', ‘Ｎ' => ‘N', ‘Ｏ' => ‘O',
  ‘Ｐ' => ‘P', ‘Ｑ' => ‘Q', ‘Ｒ' => ‘R', ‘Ｓ' => ‘S', ‘Ｔ' => ‘T',
  ‘Ｕ' => ‘U', ‘Ｖ' => ‘V', ‘Ｗ' => ‘W', ‘Ｘ' => ‘X', ‘Ｙ' => ‘Y',
  ‘Ｚ' => ‘Z', ‘ａ' => ‘a', ‘ｂ' => ‘b', ‘ｃ' => ‘c', ‘ｄ' => ‘d',
  ‘ｅ' => ‘e', ‘ｆ' => ‘f', ‘ｇ' => ‘g', ‘ｈ' => ‘h', ‘ｉ' => ‘i',
  ‘ｊ' => ‘j', ‘ｋ' => ‘k', ‘ｌ' => ‘l', ‘ｍ' => ‘m', ‘ｎ' => ‘n',
  ‘ｏ' => ‘o', ‘ｐ' => ‘p', ‘ｑ' => ‘q', ‘ｒ' => ‘r', ‘ｓ' => ‘s',
  ‘ｔ' => ‘t', ‘ｕ' => ‘u', ‘ｖ' => ‘v', ‘ｗ' => ‘w', ‘ｘ' => ‘x',
  ‘ｙ' => ‘y', ‘ｚ' => ‘z',
  ‘（' => ‘(‘, ‘）' => ‘)', ‘〔' => ‘[‘, ‘〕' => ‘]', ‘【' => ‘[‘,
  ‘】' => ‘]', ‘〖' => ‘[‘, ‘〗' => ‘]', ‘”‘ => ‘[‘, ‘”‘ => ‘]',
  ‘\” => ‘[‘, ‘\” => ‘]', ‘｛' => ‘{‘, ‘｝' => ‘}', ‘《' => ‘<‘,
  ‘》' => ‘>',
  ‘％' => ‘%', ‘＋' => ‘+', ‘—' => ‘-‘, ‘－' => ‘-‘, ‘～' => ‘-‘,
  ‘：' => ‘:', ‘。' => ‘.', ‘、' => ‘,', ‘，' => ‘.', ‘、' => ‘.',
  ‘；' => ‘,', ‘？' => ‘?', ‘！' => ‘!', ‘…' => ‘-‘, ‘‖' => ‘|',
  ‘”‘ => ‘”‘, ‘\” => ‘`', ‘\” => ‘`', ‘｜' => ‘|', ‘〃' => ‘”‘,
  ‘　' => ‘ ‘);
  ”'

# 全角转半角
print(DBC2SBC(s))

# 半角转全角
print(SBC2DBC(s))

s = ”'中文测试”'

# 全角转半角
print(DBC2SBC(s))

# 半角转全角
print(SBC2DBC(s))

四、总结

以上内容即为本文的全部介绍，希望能为各位在学习或工作中提供协助。若有任何疑问，欢迎留言交流，感谢对本站的支持。

五、参考资料

http://thinkerou.com/2015-06/covert-dbc-sbc/