使用 Python 和 Regex 查找字符串中的所有中文文本

Question

今天我需要从一堆字符串中去掉中文，并且正在寻找一个简单的 Python 正则表达式。有什么建议吗？

Answer 1

Python 2：

#!/usr/bin/env python
# -*- encoding: utf8 -*-


import re

sample = u'I am from 美国。We should be friends. 朋友。'
for n in re.findall(ur'[\u4e00-\u9fff]+',sample):
    print n

Python 3：

sample = 'I am from 美国。We should be friends. 朋友。'
for n in re.findall(r'[\u4e00-\u9fff]+', sample):
    print(n)

输出：

美国
朋友

关于Unicode 代码块：

4E00—9FFF 范围涵盖CJK 统一表意文字（CJK=中文、日文和韩文）。有许多较低的范围在某种程度上与 CJK 相关：

31C0—31EF CJK Strokes
31F0—31FF Katakana Phonetic Extensions
3200—32FF Enclosed CJK Letters and Months
3300—33FF CJK Compatibility
3400—4DBF CJK Unified Ideographs Extension A
4DC0—4DFF Yijing Hexagram Symbols
4E00—9FFF CJK Unified Ideographs 

Answer 2

python 的窄 Unicode 构建的简短但相对全面的答案（不包括序数 > 65535，它只能通过代理项对在窄 Unicode 构建中表示）：

RE = re.compile(u'[⺀-⺙⺛-⻳⼀-⿕々〇〡-〩〸-〺〻㐀-䶵一-鿃豈-鶴侮-頻並-龎]', re.UNICODE)
nochinese = RE.sub('', mystring)

用于构建 RE 的代码，以及是否需要检测用于宽构建的补充平面：

import re

LHan = [[0x2E80, 0x2E99],    # Han # So  [26] CJK RADICAL REPEAT, CJK RADICAL RAP
        [0x2E9B, 0x2EF3],    # Han # So  [89] CJK RADICAL CHOKE, CJK RADICAL C-SIMPLIFIED TURTLE
        [0x2F00, 0x2FD5],    # Han # So [214] KANGXI RADICAL ONE, KANGXI RADICAL FLUTE
        0x3005,              # Han # Lm       IDEOGRAPHIC ITERATION MARK
        0x3007,              # Han # Nl       IDEOGRAPHIC NUMBER ZERO
        [0x3021, 0x3029],    # Han # Nl   [9] HANGZHOU NUMERAL ONE, HANGZHOU NUMERAL NINE
        [0x3038, 0x303A],    # Han # Nl   [3] HANGZHOU NUMERAL TEN, HANGZHOU NUMERAL THIRTY
        0x303B,              # Han # Lm       VERTICAL IDEOGRAPHIC ITERATION MARK
        [0x3400, 0x4DB5],    # Han # Lo [6582] CJK UNIFIED IDEOGRAPH-3400, CJK UNIFIED IDEOGRAPH-4DB5
        [0x4E00, 0x9FC3],    # Han # Lo [20932] CJK UNIFIED IDEOGRAPH-4E00, CJK UNIFIED IDEOGRAPH-9FC3
        [0xF900, 0xFA2D],    # Han # Lo [302] CJK COMPATIBILITY IDEOGRAPH-F900, CJK COMPATIBILITY IDEOGRAPH-FA2D
        [0xFA30, 0xFA6A],    # Han # Lo  [59] CJK COMPATIBILITY IDEOGRAPH-FA30, CJK COMPATIBILITY IDEOGRAPH-FA6A
        [0xFA70, 0xFAD9],    # Han # Lo [106] CJK COMPATIBILITY IDEOGRAPH-FA70, CJK COMPATIBILITY IDEOGRAPH-FAD9
        [0x20000, 0x2A6D6],  # Han # Lo [42711] CJK UNIFIED IDEOGRAPH-20000, CJK UNIFIED IDEOGRAPH-2A6D6
        [0x2F800, 0x2FA1D]]  # Han # Lo [542] CJK COMPATIBILITY IDEOGRAPH-2F800, CJK COMPATIBILITY IDEOGRAPH-2FA1D

def build_re():
    L = []
    for i in LHan:
        if isinstance(i, list):
            f, t = i
            f = chr(f)
            t = chr(t)
            L.append(f'{f}-{t}')
        else:
            L.append(chr(i))
    
    RE = '[%s]' % ''.join(L)
    print('RE:', RE)
    return re.compile(RE, re.UNICODE)

RE = build_re()
print(RE.sub('', u'美国'))
print(RE.sub('', u'blah'))