如何讓你的Python程序支持多語言

本文介紹如何通過Python標準庫gettext幫助你的程序支持多語言。

代碼例子

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:        breakif 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))

這是我們一個簡單的猜數字游戲，我們執行看看過程。

$ python3 guess.py Hello! What's your name?AidanWell, Aidan, I am thinking of a number between 1 and 20.Take a guess.13You guess is too high.Take a guess.2Your guess is too low.Take a guess.12You guess is too high.Take a guess.1Your guess is too low.Take a guess.10You guess is too high.Take a guess.9Good 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，那么我們通常可能選擇將字符串全部修改為相應中文，但是老板要讓你自己針對不同用戶不同語言就麻煩了。那有啥辦法呢？Python標準庫gettext可以幫助我們。

改造

我們首先用_()，然改造我們的字符串。你可以把_()想象成類似如下函數

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]

不過，當我查看他類型時，我發現他應該是某種繼承了list的擴展類型。

>>> type(_)<class 'list'>

改造后我們的代碼如下

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:        breakif 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 自帶一個工具我們提取使用_()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:5msgid "Hello! What's your name?"msgstr ""#: guess.py:9msgid "Well, {}, I am thinking of a number between 1 and 20."msgstr ""#: guess.py:12msgid "Take a guess."msgstr ""#: guess.py:17msgid "You should give me a number."msgstr ""#: guess.py:21msgid "Your guess is too low."msgstr ""#: guess.py:24msgid "You guess is too high."msgstr ""#: guess.py:30msgid "Good job, {}! You guessed my number in {} guesses!"msgstr ""#: guess.py:34msgid "Nope. The number I was thinking of was {}."msgstr ""

翻譯工作

我們通過使用poedit這個非常好用的工具對其翻譯成我們想要的目標文件，該工具還帶有翻譯詞典，跨平臺。地址：http://poedit.net/

翻譯后的結果

翻譯后生成

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:5msgid "Hello! What's your name?"msgstr "你好！你叫什么名字？"#: guess.py:9msgid "Well, {}, I am thinking of a number between 1 and 20."msgstr "好的，{}，我心里想了個1到20之間的數。"#: guess.py:12msgid "Take a guess."msgstr "猜猜看。"#: guess.py:17msgid "You should give me a number."msgstr "你應該給我個數字。"#: guess.py:21msgid "Your guess is too low."msgstr "你猜低了。"#: guess.py:24msgid "You guess is too high."msgstr "你猜高了。"#: guess.py:30msgid "Good job, {}! You guessed my number in {} guesses!"msgstr "漂亮，{}！你用了{}次猜中了我的數字。"#: guess.py:34msgid "Nope. The number I was thinking of was {}."msgstr "不對。我想的數字是{}。"

還有一個mo擴展的文件，MO 文件是面向計算機的、由 PO 文件通過 gettext 軟件包編譯而成的二進制文件。

我們如下放置這兩個文件

├── guess.py
├── locale
│ └── zh_CN
│ └── LC_MESSAGES
│ ├── guess.mo
│ └── guess.po

武裝gettext

然后我們在代碼加入

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

終極版本

import randomimport gettextes = gettext.translation('guess', localedir='locale', languages=['zh_CN'])es.install()guessesTaken = 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:        breakif 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))

驚人結果

$ python3 guess.py 你好！你叫什么名字？大熊好的，大熊，我心里想了個1到20之間的數。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次猜中了我的數字。

結論

Python 在國際化操作方面很簡單，你是否有更好的方案？