吴贺华 发表于 2015-4-22 08:22:57

如何让你的Python程序支持多语言

如何让你的Python程序支持多语言
  本文介绍如何通过Python标准库gettext帮助你的程序支持多语言。

代码例子
  

import random  

  
guessesTaken = 0
  

  
print(_("Hello! What's your name?"))
  
myName = input()
  

  
number = random.randint(1, 20)
  
print("Well, {}, I am thinking of a number between 1 and 20.".format(myName))
  

  
while guessesTaken < 6:
  print("Take a guess.")
  guess = input()
  try:
  guess = int(guess)
  except ValueError:
  print("You should give me a number.")
  continue
  

  if guess < number:
  print("Your guess is too low.")
  

  if guess > number:
  print("You guess is too high.")
  

  if guess == number:
  break
  

  
if guess == number:
  print("Good job, {}! You guessed my number in {} guesses!".format(
  myName, guessesTaken))
  

  
if guess != number:
  print("Nope. The number I was thinking of was {}.".format(number))
  

  这是我们一个简单的猜数字游戏,我们执行看看过程。
  

$ python3 guess.py  
Hello! What's your name?
  
Aidan
  
Well, Aidan, I am thinking of a number between 1 and 20.
  
Take a guess.
  
13
  
You guess is too high.
  
Take a guess.
  
2
  
Your guess is too low.
  
Take a guess.
  
12
  
You guess is too high.
  
Take a guess.
  
1
  
Your guess is too low.
  
Take a guess.
  
10
  
You guess is too high.
  
Take a guess.
  
9
  
Good job, Aidan! You guessed my number in 6 guesses!
  

  程序是很漂亮了,可是老板突然要求你改成中文的,那么我们通常可能选择将字符串全部修改为相应中文,但是老板要让你自己针对不同用户不同语言就麻烦了。那有啥办法呢?Python标准库gettext可以帮助我们。

改造
  我们首先用_(),然改造我们的字符串。你可以把_()想象成类似如下函数
  

def _(s):  spanishStrings = {'Hello world!': 'Hola Mundo!'}
  frenchStrings = {'Hello world!': 'Bonjour le monde!'}
  germanStrings = {'Hello world!': 'Hallo Welt!'}
  

  if LANGUAGE == 'English':
  return s
  if LANGUAGE == 'Spanish':
  return spanishStrings
  if LANGUAGE == 'French':
  return frenchStrings
  if LANGUAGE == 'German':
  return germanStrings
  

  不过,当我查看他类型时,我发现他应该是某种继承了list的扩展类型。
  

>>> type(_)  

  

  改造后我们的代码如下
  

import random  

  
guessesTaken = 0
  

  
print(_("Hello! What's your name?"))
  
myName = input()
  

  
number = random.randint(1, 20)
  
print(_("Well, {}, I am thinking of a number between 1 and 20.").format(myName))
  

  
while guessesTaken < 6:
  guessesTaken += 1
  print(_("Take a guess."))
  guess = input()
  try:
  guess = int(guess)
  except ValueError:
  print(_("You should give me a number."))
  continue
  

  if guess < number:
  print(_("Your guess is too low."))
  

  if guess > number:
  print(_("You guess is too high."))
  

  if guess == number:
  break
  

  
if guess == number:
  print(_("Good job, {}! You guessed my number in {} guesses!").format(
  myName, guessesTaken))
  

  
if guess != number:
  print(_("Nope. The number I was thinking of was {}.").format(number))
  

提取字符串
  Python 自带一个工具我们提取使用_()包裹的字符串
  

pygettext3 -d guess guess.py  

  它生成了如下文件:
  

$ cat guess.pot  
# SOME DESCRIPTIVE>  
# Copyright (C) YEAR ORGANIZATION
  
# FIRST AUTHOR , YEAR.
  
#
  
msgid ""
  
msgstr ""
  
"Project-Id-Version: PACKAGE VERSION\n"
  
"POT-Creation-Date: 2014-12-24 15:35+CST\n"
  
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
  
"Last-Translator: FULL NAME \n"
  
"Language-Team: LANGUAGE \n"
  
"MIME-Version: 1.0\n"
  
"Content-Type: text/plain; \n"
  
"Content-Transfer-Encoding: 8bit\n"
  
"Generated-By: pygettext.py 1.5\n"
  

  

  
#: guess.py:5
  
msgid "Hello! What's your name?"
  
msgstr ""
  

  
#: guess.py:9
  
msgid "Well, {}, I am thinking of a number between 1 and 20."
  
msgstr ""
  

  
#: guess.py:12
  
msgid "Take a guess."
  
msgstr ""
  

  
#: guess.py:17
  
msgid "You should give me a number."
  
msgstr ""
  

  
#: guess.py:21
  
msgid "Your guess is too low."
  
msgstr ""
  

  
#: guess.py:24
  
msgid "You guess is too high."
  
msgstr ""
  

  
#: guess.py:30
  
msgid "Good job, {}! You guessed my number in {} guesses!"
  
msgstr ""
  

  
#: guess.py:34
  
msgid "Nope. The number I was thinking of was {}."
  
msgstr ""
  

翻译工作
  我们通过使用poedit这个非常好用的工具对其翻译成我们想要的目标文件,该工具还带有翻译词典,跨平台。地址:http://poedit.net/


翻译后的结果
  翻译后生成
  guess.po
  

# SOME DESCRIPTIVE>
# Copyright (C) YEAR ORGANIZATION
  
# FIRST AUTHOR , YEAR.
  
#
  
msgid ""
  
msgstr ""
  
"Project-Id-Version: \n"
  
"POT-Creation-Date: 2014-12-24 15:35+CST\n"
  
"PO-Revision-Date: 2014-12-24 16:23+0800\n"
  
"Last-Translator: \n"
  
"Language-Team: \n"
  
"MIME-Version: 1.0\n"
  
"Content-Type: text/plain; charset=UTF-8\n"
  
"Content-Transfer-Encoding: 8bit\n"
  
"Generated-By: pygettext.py 1.5\n"
  
"X-Generator: Poedit 1.7.1\n"
  
"Plural-Forms: nplurals=1; plural=0;\n"
  
"Language: zh\n"
  

  
#: guess.py:5
  
msgid "Hello! What's your name?"
  
msgstr "你好!你叫什么名字?"
  

  
#: guess.py:9
  
msgid "Well, {}, I am thinking of a number between 1 and 20."
  
msgstr "好的,{},我心里想了个1到20之间的数。"
  

  
#: guess.py:12
  
msgid "Take a guess."
  
msgstr "猜猜看。"
  

  
#: guess.py:17
  
msgid "You should give me a number."
  
msgstr "你应该给我个数字。"
  

  
#: guess.py:21
  
msgid "Your guess is too low."
  
msgstr "你猜低了。"
  

  
#: guess.py:24
  
msgid "You guess is too high."
  
msgstr "你猜高了。"
  

  
#: guess.py:30
  
msgid "Good job, {}! You guessed my number in {} guesses!"
  
msgstr "漂亮,{}!你用了{}次猜中了我的数字。"
  

  
#: guess.py:34
  
msgid "Nope. The number I was thinking of was {}."
  
msgstr "不对。我想的数字是{}。"
  

  还有一个mo扩展的文件,MO 文件是面向计算机的、由 PO 文件通过 gettext 软件包编译而成的二进制文件。
  我们如下放置这两个文件
  ├── guess.py
  ├── locale
  │ └── zh_CN
  │ └── LC_MESSAGES
  │ ├── guess.mo
  │ └── guess.po

武装gettext
  然后我们在代码加入
  

import gettext  

  
es = gettext.translation('guess', localedir='locale', languages=['zh_CN'])
  
es.install()
  

终极版本
  

import random  
import gettext
  

  
es = gettext.translation('guess', localedir='locale', languages=['zh_CN'])
  
es.install()
  

  
guessesTaken = 0
  

  
print(_("Hello! What's your name?"))
  
myName = input()
  

  
number = random.randint(1, 20)
  
print(_("Well, {}, I am thinking of a number between 1 and 20.").format(myName))
  

  
while guessesTaken < 6:
  guessesTaken += 1
  print(_("Take a guess."))
  guess = input()
  try:
  guess = int(guess)
  except ValueError:
  print(_("You should give me a number."))
  continue
  

  if guess < number:
  print(_("Your guess is too low."))
  

  if guess > number:
  print(_("You guess is too high."))
  

  if guess == number:
  break
  

  
if guess == number:
  print(_("Good job, {}! You guessed my number in {} guesses!").format(
  myName, guessesTaken))
  

  
if guess != number:
  print(_("Nope. The number I was thinking of was {}.").format(number))
  

惊人结果
  

$ python3 guess.py  
你好!你叫什么名字?
  
大熊
  
好的,大熊,我心里想了个1到20之间的数。
  
猜猜看。
  
10
  
你猜高了。
  
猜猜看。
  
8
  
你猜高了。
  
猜猜看。
  
6
  
你猜高了。
  
猜猜看。
  
4
  
漂亮,大熊!你用了4次猜中了我的数字。
  

结论
  

Python 在国际化操作方面很简单,你是否有更好的方案?
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