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 randomguessesTaken = 0print(_("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[s] if LANGUAGE == 'French': return frenchStrings[s] if LANGUAGE == 'German': return germanStrings[s]

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(_)
<class 'list'>

改造后我们的代码如下

import randomguessesTaken = 0print(_("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 TITLE.
# Copyright (C) YEAR ORGANIZATION
# FIRST AUTHOR <EMAIL@ADDRESS>, 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 <EMAIL@ADDRESS>\n" "Language-Team: LANGUAGE <LL@li.org>\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" #: 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 TITLE.
# Copyright (C) YEAR ORGANIZATION
# FIRST AUTHOR <EMAIL@ADDRESS>, 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 gettextes = gettext.translation('guess', localedir='locale', languages=['zh_CN'])
es.install()

终极版本

import random
import gettextes = 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？