我能检测unicode字符串的语言代码吗？

Question

我遇到了一个情况，我正在读取一串文本，我需要识别出它的语言代码（比如 en、de、fr、es 等等）。

在 Python 中有没有简单的方法可以做到这一点？

Answer 1

看看这个 guess-language:

它试图判断一段Unicode（utf-8）文本的自然语言。

不过，正如名字所说，它只是“猜”语言。你不能指望结果百分之百正确。

补充说明：

guess-language 这个项目已经不再维护了。不过有一个分支（支持python3）： guess_language-spirit

Answer 2

在我的情况下，我只需要判断两种语言，所以我只检查第一个字符：

import unicodedata

def is_greek(term):
    return 'GREEK' in unicodedata.name(term.strip()[0])


def is_hebrew(term):
    return 'HEBREW' in unicodedata.name(term.strip()[0])

Answer 3

如果你需要根据用户的操作来检测语言，可以使用谷歌的Ajax语言API：

#!/usr/bin/env python
import json
import urllib, urllib2

def detect_language(text,
    userip=None,
    referrer="http://stackoverflow.com/q/4545977/4279",
    api_key=None):        

    query = {'q': text.encode('utf-8') if isinstance(text, unicode) else text}
    if userip: query.update(userip=userip)
    if api_key: query.update(key=api_key)

    url = 'https://ajax.googleapis.com/ajax/services/language/detect?v=1.0&%s'%(
        urllib.urlencode(query))

    request = urllib2.Request(url, None, headers=dict(Referer=referrer))
    d = json.load(urllib2.urlopen(request))

    if d['responseStatus'] != 200 or u'error' in d['responseData']:
        raise IOError(d)

    return d['responseData']['language']

print detect_language("Python - can I detect unicode string language code?")

输出结果

en

谷歌翻译API v2

默认限制是每天100000个字符（一次最多5000个字符）。

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import json
import urllib, urllib2

from operator import itemgetter

def detect_language_v2(chunks, api_key):
    """
    chunks: either string or sequence of strings

    Return list of corresponding language codes
    """
    if isinstance(chunks, basestring):
        chunks = [chunks] 

    url = 'https://www.googleapis.com/language/translate/v2'

    data = urllib.urlencode(dict(
        q=[t.encode('utf-8') if isinstance(t, unicode) else t 
           for t in chunks],
        key=api_key,
        target="en"), doseq=1)

    # the request length MUST be < 5000
    if len(data) > 5000:
        raise ValueError("request is too long, see "
            "http://code.google.com/apis/language/translate/terms.html")

    #NOTE: use POST to allow more than 2K characters
    request = urllib2.Request(url, data,
        headers={'X-HTTP-Method-Override': 'GET'})
    d = json.load(urllib2.urlopen(request))
    if u'error' in d:
        raise IOError(d)
    return map(itemgetter('detectedSourceLanguage'), d['data']['translations'])

现在你可以明确请求检测语言：

def detect_language_v2(chunks, api_key):
    """
    chunks: either string or sequence of strings

    Return list of corresponding language codes
    """
    if isinstance(chunks, basestring):
        chunks = [chunks] 

    url = 'https://www.googleapis.com/language/translate/v2/detect'

    data = urllib.urlencode(dict(
        q=[t.encode('utf-8') if isinstance(t, unicode) else t
           for t in chunks],
        key=api_key), doseq=True)

    # the request length MUST be < 5000
    if len(data) > 5000:
        raise ValueError("request is too long, see "
            "http://code.google.com/apis/language/translate/terms.html")

    #NOTE: use POST to allow more than 2K characters
    request = urllib2.Request(url, data,
        headers={'X-HTTP-Method-Override': 'GET'})
    d = json.load(urllib2.urlopen(request))

    return [sorted(L, key=itemgetter('confidence'))[-1]['language']
            for L in d['data']['detections']]

示例：

print detect_language_v2(
    ["Python - can I detect unicode string language code?",
     u"матрёшка",
     u"打水"], api_key=open('api_key.txt').read().strip())

输出结果

[u'en', u'ru', u'zh-CN']