如何引用函数的返回值？

Question

My assignment is to use nested if statements to construct a simple translator. Yes, I know that's an awful way to do it, but that's what the assignment says. Here's what I have so far:

def translate(word, language):
    '''
    Takes as parameters a string to translate,
    and a second string as the language to translate to.
    Returns the original word, the language, and the word's
    translation in the entered language.
    '''
    en_word = word.lower()
    lang = language.lower()

    #   French
    if lang == "french":
        if en_word == "cat":
            print("chat")            
    if lang == "french":
        if en_word == "dog":
            print("chein")

    #   German      
    if lang == "german":
        if en_word == "cat":
            print("katze")
    if lang == "german":
        if en_word == "dog":
            print("hund")

    #   Spanish      
    if lang == "spanish":
        if en_word == "cat":
            print("gato")
    if lang == "spanish":
        if en_word == "dog":
            print("perro")

translate('cat', 'french')

After being called as translate('cat', 'french') , for example, the output should be:
The translation of cat in French is chat

As it is, my function finds and prints the correct word. I tried using a return statement such as

return en_word, 'French', 'chat' and a print statement such as

print('The translation of', translate[0], 'into', translate[1], 'is', translate[2])

but the error message TypeError: 'function' object is not subscriptable popped up. I could put virtually identical print statements into each end of the if statements in the function, but that seems terribly inelegant.

How can I get the function to return the English word, the language and the translated word to insert into a generic print statement?

Answer 1

用return语句替换print函数？

Answer 2

Here is an example of how you can restructure your code.

def translate(word, language):

    en_word = word.lower()
    lang = language.lower()

    if lang == "french":
        if en_word == "cat":
            return "chat"
        elif en_word == "dog":
            return "chein"

    elif lang == "german":
        if en_word == "cat":
            return "katze"
        elif en_word == "dog":
            return "hund"

    elif lang == "spanish":
        if en_word == "cat":
            return "gato"
        elif en_word == "dog":
            return "perro"

myword = 'cat'
mylanguage = 'french'

res = translate(myword, mylanguage)
print('The translation of {0} in {1} is {2}'.format(myword, mylanguage.title(), res))

Explanation

• Use elif instead of unnecessary repeated if statements.
• Have your function return a value instead of print .
• Use str.format to incorporate variables in your print statement outside your function.

Answer 3

I guess this is specified by your assignment, but in real life, I would use a dictionary of dictionaries as the basis of your ... dictionary and not a bunch of if statements:

def translate(word,language):
    dictionary = {
      "french": {"cat":"chat",
                 "dog":"chien"},
      "german": {"cat":"katze",
                 "dog":"hund"},
      "spanish": {"cat":"gato",
                  "dog":"perro"}
     }
return(dictionary.get(language).get(word,word))

This yields:

>>> translate("cat","french")
'chat'
>>> translate("cat","german")
'katze'
>>> translate("dog","german")
'hund'
>>> translate("mouse","spanish")
'mouse'

Here it returns the original word if it is not found. You'd want to build in error handling for words or languages that weren't in dictionary,