How to convert full-width and half-width characters in Python-Python Tutorial-php.cn

前言

相信对于每一个编程人员来说，在文本处理的时候，经常会遇到全角半角不一致的问题。于是需要程序能够快速的在两者之间互转。由于全角半角本身存在着映射关系，所以处理起来并不复杂。

具体规则为：

全角字符unicode编码从65281~65374 （十六进制 0xFF01 ~ 0xFF5E）

半角字符unicode编码从33~126 （十六进制 0x21~ 0x7E）

空格比较特殊，全角为 12288（0x3000），半角为 32（0x20）

而且除空格外，全角/半角按unicode编码排序在顺序上是对应的（半角 + 65248 = 全角）

所以可以直接通过用+-法来处理非空格数据，对空格单独处理。

用到的一些函数

chr()函数用一个范围在range（256）内的（就是0～255）整数作参数，返回一个对应的字符。

unichr()跟它一样，只不过返回的是Unicode字符。

ord()函数是chr()函数或unichr()函数的配对函数，它以一个字符（长度为1的字符串）作为参数，返回对应的ASCII数值，或者Unicode数值。

先来打印下映射关系：

for i in xrange(33,127):
 print i,chr(i),i+65248,unichr(i+65248)

Copy after login

返回结果

33 ! 65281 ！
34 " 65282 ＂
35 # 65283 ＃
36 $ 65284 ＄
37 % 65285 ％
38 & 65286 ＆
39 ' 65287 ＇
40 ( 65288 （
41 ) 65289 ）
42 * 65290 ＊
43 + 65291 ＋
44 , 65292 ，
45 - 65293 －
46 . 65294 ．
47 / 65295 ／
48 0 65296 ０
49 1 65297 １
50 2 65298 ２
51 3 65299 ３
52 4 65300 ４
53 5 65301 ５
54 6 65302 ６
55 7 65303 ７
56 8 65304 ８
57 9 65305 ９
58 : 65306 ：
59 ; 65307 ；
60 < 65308 ＜
61 = 65309 ＝
62 > 65310 ＞
63 &#63; 65311 ？
64 @ 65312 ＠
65 A 65313 Ａ
66 B 65314 Ｂ
67 C 65315 Ｃ
68 D 65316 Ｄ
69 E 65317 Ｅ
70 F 65318 Ｆ
71 G 65319 Ｇ
72 H 65320 Ｈ
73 I 65321 Ｉ
74 J 65322 Ｊ
75 K 65323 Ｋ
76 L 65324 Ｌ
77 M 65325 Ｍ
78 N 65326 Ｎ
79 O 65327 Ｏ
80 P 65328 Ｐ
81 Q 65329 Ｑ
82 R 65330 Ｒ
83 S 65331 Ｓ
84 T 65332 Ｔ
85 U 65333 Ｕ
86 V 65334 Ｖ
87 W 65335 Ｗ
88 X 65336 Ｘ
89 Y 65337 Ｙ
90 Z 65338 Ｚ
91 [ 65339 ［
92 \ 65340 ＼
93 ] 65341 ］
94 ^ 65342 ＾
95 _ 65343 ＿
96 ` 65344 ｀
97 a 65345 ａ
98 b 65346 ｂ
99 c 65347 ｃ
100 d 65348 ｄ
101 e 65349 ｅ
102 f 65350 ｆ
103 g 65351 ｇ
104 h 65352 ｈ
105 i 65353 ｉ
106 j 65354 ｊ
107 k 65355 ｋ
108 l 65356 ｌ
109 m 65357 ｍ
110 n 65358 ｎ
111 o 65359 ｏ
112 p 65360 ｐ
113 q 65361 ｑ
114 r 65362 ｒ
115 s 65363 ｓ
116 t 65364 ｔ
117 u 65365 ｕ
118 v 65366 ｖ
119 w 65367 ｗ
120 x 65368 ｘ
121 y 65369 ｙ
122 z 65370 ｚ
123 { 65371 ｛
124 | 65372 ｜
125 } 65373 ｝
126 ~ 65374 ～

Copy after login

把全角转成半角：

def full2half(s):
 n = []
 s = s.decode('utf-8')
 for char in s:
 num = ord(char)
 if num == 0x3000:
  num = 32
 elif 0xFF01 <= num <= 0xFF5E:
  num -= 0xfee0
 num = unichr(num)
 n.append(num)
return ''.join(n)

Copy after login

把半角转成全角：

def half2full(s):
 n = []
 s = s.decode('utf-8')
 for char in s:
 num = char(char)
 if num == 320:
  num = 0x3000
 elif 0x21 <= num <= 0x7E:
  num += 0xfee0
 num = unichr(num)
 n.append(num)
return ''.join(n)

Copy after login

上面的实现方式非常的简单，但是现实情况下可能并不会把所以的字符统一进行转换，比如中文文章中我们期望将所有出现的字母和数字全部转化成半角，而常见标点符号统一使用全角，上面的转化就不适合了。

解决方案，是自定义词典。

#!/usr/bin/env python
# -*- coding: utf-8 -*-
 
FH_SPACE = FHS = ((u"　", u" "),)
FH_NUM = FHN = (
 (u"０", u"0"), (u"１", u"1"), (u"２", u"2"), (u"３", u"3"), (u"４", u"4"),
 (u"５", u"5"), (u"６", u"6"), (u"７", u"7"), (u"８", u"8"), (u"９", u"9"),
)
FH_ALPHA = FHA = (
 (u"ａ", u"a"), (u"ｂ", u"b"), (u"ｃ", u"c"), (u"ｄ", u"d"), (u"ｅ", u"e"),
 (u"ｆ", u"f"), (u"ｇ", u"g"), (u"ｈ", u"h"), (u"ｉ", u"i"), (u"ｊ", u"j"),
 (u"ｋ", u"k"), (u"ｌ", u"l"), (u"ｍ", u"m"), (u"ｎ", u"n"), (u"ｏ", u"o"),
 (u"ｐ", u"p"), (u"ｑ", u"q"), (u"ｒ", u"r"), (u"ｓ", u"s"), (u"ｔ", u"t"),
 (u"ｕ", u"u"), (u"ｖ", u"v"), (u"ｗ", u"w"), (u"ｘ", u"x"), (u"ｙ", u"y"), (u"ｚ", u"z"),
 (u"Ａ", u"A"), (u"Ｂ", u"B"), (u"Ｃ", u"C"), (u"Ｄ", u"D"), (u"Ｅ", u"E"),
 (u"Ｆ", u"F"), (u"Ｇ", u"G"), (u"Ｈ", u"H"), (u"Ｉ", u"I"), (u"Ｊ", u"J"),
 (u"Ｋ", u"K"), (u"Ｌ", u"L"), (u"Ｍ", u"M"), (u"Ｎ", u"N"), (u"Ｏ", u"O"),
 (u"Ｐ", u"P"), (u"Ｑ", u"Q"), (u"Ｒ", u"R"), (u"Ｓ", u"S"), (u"Ｔ", u"T"),
 (u"Ｕ", u"U"), (u"Ｖ", u"V"), (u"Ｗ", u"W"), (u"Ｘ", u"X"), (u"Ｙ", u"Y"), (u"Ｚ", u"Z"),
)
FH_PUNCTUATION = FHP = (
 (u"．", u"."), (u"，", u","), (u"！", u"!"), (u"？", u"&#63;"), (u"”", u'"'),
 (u"'", u"'"), (u"‘", u"`"), (u"＠", u"@"), (u"＿", u"_"), (u"：", u":"),
 (u"；", u";"), (u"＃", u"#"), (u"＄", u"$"), (u"％", u"%"), (u"＆", u"&"),
 (u"（", u"("), (u"）", u")"), (u"‐", u"-"), (u"＝", u"="), (u"＊", u"*"),
 (u"＋", u"+"), (u"－", u"-"), (u"／", u"/"), (u"＜", u"<"), (u"＞", u">"),
 (u"［", u"["), (u"￥", u"\\"), (u"］", u"]"), (u"＾", u"^"), (u"｛", u"{"),
 (u"｜", u"|"), (u"｝", u"}"), (u"～", u"~"),
)
FH_ASCII = HAC = lambda: ((fr, to) for m in (FH_ALPHA, FH_NUM, FH_PUNCTUATION) for fr, to in m)
 
HF_SPACE = HFS = ((u" ", u"　"),)
HF_NUM = HFN = lambda: ((h, z) for z, h in FH_NUM)
HF_ALPHA = HFA = lambda: ((h, z) for z, h in FH_ALPHA)
HF_PUNCTUATION = HFP = lambda: ((h, z) for z, h in FH_PUNCTUATION)
HF_ASCII = ZAC = lambda: ((h, z) for z, h in FH_ASCII())
 
 
def convert(text, *maps, **ops):
 """ 全角/半角转换
 args:
 text: unicode string need to convert
 maps: conversion maps
 skip: skip out of character. In a tuple or string
 return: converted unicode string
 """
 
 if "skip" in ops:
 skip = ops["skip"]
 if isinstance(skip, basestring):
  skip = tuple(skip)
 
 def replace(text, fr, to):
  return text if fr in skip else text.replace(fr, to)
 else:
 def replace(text, fr, to):
  return text.replace(fr, to)
 
 for m in maps:
 if callable(m):
  m = m()
 elif isinstance(m, dict):
  m = m.items()
 for fr, to in m:
  text = replace(text, fr, to)
 return text
 
 
if __name__ == '__main__':
 text = u"成田空港—【ＪＲ特急成田エクスプレス号&#12539;横浜行，2站】—東京—【ＪＲ新幹線はやぶさ号&#12539;新青森行,6站 】—新青森—【ＪＲ特急スーパー白鳥号&#12539;函館行，4站 】—函館"
print convert(text, FH_ASCII, {u"【": u"[", u"】": u"]", u",": u"，", u".": u"。", u"&#63;": u"？", u"!": u"！"}, spit="，。？！“”")

Copy after login

特别注意：引号在英语体系中引号是不区分前引号和后引号。

总结

以上就是关于Python实现全角半角字符互转的方法，希望本文的内容对大家的学习或者工作能带来一定的帮助，如果有疑问大家可以留言交流。

Related labels：

python Full-width and half-width conversion full-width characters

source：php.cn

Previous article：Python crawler multi-threading detailed explanation and example code Next article：python string, numerical calculation

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn