如何让你的Python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[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 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 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 ""

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