如何捕获字符串中直到第一个元音的字符并从中创建子字符串？

Question

目前，我的代码的第一部分工作正常。如果它检测到第一个字符（索引 0）是元音，它会停止并在单词末尾添加“yay”。

第二部分旨在捕捉到第一个元音的辅音。这可以正常工作。

当我尝试获取原始单词并将所有内容切掉到第一个元音并从中创建一个新的子字符串时，就会出现问题。这意味着如果用户输入“hello”，它应该输出“ellohay”。我可以得到“hellohay”，但不知道如何捕捉这些初始辅音并将它们切掉。

# Pig Latinify

vowels = ['a', 'e', 'i', 'o', 'u']
consonants = ['b', 'c', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm', 'n', 'p', 'q', 'r', 's', 't', 'v', 'w', 'x', 'z']


def pig_latinify():
    state = True
    while state == True:

        user_input = raw_input("Enter a word to be translated: ").lower()

        # If the first character in input is a vowel add 'yay' to input and print.
        if user_input[0] in vowels[0:]:
            print ""
            print "Begins with a vowel." 
            pig_output = user_input + "yay"
            print user_input, "becomes:", pig_output
            print ""
        else:
            print ""
            print "Doesn't begin with a vowel."

            captured_consonants = ""
            captured_substring = ""
            new_user_input = ""

            # Capture the consonants up to the first vowel
            for i in user_input:
                if i in vowels:
                    break
                if i in consonants:
                    captured_consonants = captured_consonants + i

            # Slice user_input up to the first vowel and create a substring beginng from the first vowel until the end of the string.
                if i in consonants:
                    break
                if i in vowels:
                    captured_substring = captured_substring + i 
                print captured_substring

            # Concatenate substring of user_input with captured_consonants and 'ay'
            pig_output = captured_substring + captured_consonants + "ay"
            print user_input, "becomes:", pig_output
            print ""

pig_latinify()

Answer 1

如果你想删除所有前导字符直到你碰到一个元音，你可以使用itertools.dropwhile：

from itertools import dropwhile
user_input = "hello"

vowels = {"a","e","i","o","u"}

up_to = "".join(dropwhile(lambda x: x not in vowels, user_input))
print(up_to + user_input[:len(user_input) - len(up_to)]+"ay")

输出：你好

lambda x: x not in vowels 表示我们要删除所有字符，直到在元音中找到一个字符。如果您想使用大写或小写，请将大写元音添加到集合中或将 lambda 切换为 x.lower() not in vowels

Answer 2

这段代码看起来很奇怪。例如，第二个if i in vowels: 永远不会到达。

您可能想要：

1. 找到第一个元音的位置 - 让它成为pos
2. 检查pos是否>0
3. return user_input[pos:] + user_input[:pos-1] + 'ay'

Answer 3

使用正则表达式可能是你最好的选择：

# Pig Latinify
import re

vowels = list('aeiou')

def pig_latinify():
    state = True
    while state == True:

        user_input = raw_input("Enter a word to be translated: ").lower()

        # If the first character in input is a vowel add 'yay' to input and print.
        if user_input[0] in vowels[0:]:
            print ""
            print "Begins with a vowel." 
            pig_output = user_input + "yay"
            print user_input, "becomes:", pig_output
            print ""
        else:
            print ""
            print "Doesn't begin with a vowel."

            r = re.search("(.*?)([aeiou].*)", user_input)

            # Capture the consonants up to the first vowel
            captured_consonants = r.groups()[0]

            # Slice user_input up to the first vowel and create a substring beginng from the first vowel until the end of the string.
            captured_substring = r.groups()[1]

            # Concatenate substring of user_input with captured_consonants and 'ay'
            pig_output = captured_substring + captured_consonants + "ay"
            print user_input, "becomes:", pig_output
            print ""

pig_latinify()

这基本上是非贪婪地搜索字符串，直到它碰到一个元音，并制作两组辅音和元音+跟随的字符串，并相应地操作它们。

$ python pig_latin.py 
Enter a word to be translated: hello

Doesn't begin with a vowel.
hello becomes: ellohay

Enter a word to be translated: hi

Doesn't begin with a vowel.
hi becomes: ihay

Enter a word to be translated: apple

Begins with a vowel.
apple becomes: appleyay