Question

我知道这本备受批评的书中有很多关于这个练习的帖子，但到目前为止它帮助我开始理解这些内容。

但是，每一章都有问题，而有些我可以自己回答，有些则更复杂。

import random
from urllib import urlopen
import sys

WORD_URL = "http://learncodethehardway.org/words.txt"
WORDS = []

PHRASES = {
    "class %%%(%%%):":
       "Make a class named %%% that is-a %%%.",
    "class %%%(object):\n\tdef __init__(self, ***)" :
      "class %%% has-a __init__ that takes self and *** parameters.",
    "class %%%(object):\n\tdef ***(self, @@@)":
      "class %%% has-a function named *** that takes self and @@@ parameters.",
    "*** = %%%()":
      "Set *** to an instance of class %%%.",
    "***.***(@@@)":
      "From *** get the *** function, and call it with parameters self, @@@.",
    "***.*** = '***'":
      "From *** get the *** attribute and set it to '***'."
}

# do they want to drill phrases first
PHRASE_FIRST = False
if len(sys.argv) == 2 and sys.argv[1] == "english":
    PHRASE_FIRST = True

# load up the words from the website
for word in urlopen(WORD_URL).readlines():
    WORDS.append(word.strip())


def convert(snippet, phrase):
    class_names = [w.capitalize() for w in
                   random.sample(WORDS, snippet.count("%%%"))]
    other_names = random.sample(WORDS, snippet.count("***"))
    results = []
    param_names = []

    for i in range(0, snippet.count("@@@")):
        param_count = random.randint(1,3)
        param_names.append(', '.join(random.sample(WORDS, param_count)))

    for sentence in snippet, phrase:
        result = sentence[:]

        # fake class names
        for word in class_names:
            result = result.replace("%%%", word, 1)

        # fake other names
        for word in other_names:
            result = result.replace("***", word, 1)

        # fake parameter lists
        for word in param_names:
           result = result.replace("@@@", word, 1)

        results.append(result)

    return results


# keep going until they hit CTRL-D
try:
    while True:
        snippets = PHRASES.keys()
        random.shuffle(snippets)

        for snippet in snippets:
            phrase = PHRASES[snippet]
            question, answer = convert(snippet, phrase)
            if PHRASE_FIRST:
                question, answer = answer, question

            print question

            raw_input("> ")
            print "ANSWER:  %s\n\n" % answer
except EOFError:
    print "\nBye"

我不明白这一点

for sentence in snippet, phrase: result = sentence[:]

句子[：]假设做什么？我在没有[：]的情况下尝试了代码并且它有效，所以我很困惑。也许只是因为没有reasong让事情变得更加混乱？因为我也注意到了，

此代码：

for i in range(0, snippet.count("@@@")): param_count = random.randint(1,3) param_names.append(', '.join(random.sample(WORDS, param_count)))

我可以重写一些不那么令人困惑的东西param_names = random.sample(WORDS, snippet.count("@@@"))，这也引出了为什么这样做的问题？

很抱歉n00bish的帖子，但帮助意味着很多！

问：句子[：]学习Python艰难之路Ex。 41

0 个答案: