Python 中的条件，字母按特定顺序

Question

I am trying to find words in a corpus that have letters (specifically aeiouy) that appear in the words in that order (like facetiously). I have the following code so far, but am struggling on how to get it to have the condition that they need to be in the following order.

english = nltk.corpus.words.words()
words = [w for w in english if re.search(r'[aeiouy]',w)]

Is there any easy way to do this?

Answer 1

Try re.search(r'a[b-zB-Z]*e[b-df-zB-DF-Z]*i[b-df-hj-zB-DF-HJ-Z]*o[b-df-hj-np-zB-DF-HJ-NP-Z]*u[b-df-hj-np-tv-zB-DF-HJ-NP-TV-Z]*y',w) to allow for some (eventual) characters ([a-zA-Z]) between you letters.

Ugly is n't it.

But if you are beforehand sure that all characters are in [a-zA-Z], it can be simplified: re.search(r'a[^a]*e[^ae]*i[^aei]*o[^aeio]*u[^aeiou]*y',w)

Answer 2

How about re.search('a[^iouy]*e[^aouy]*i[^aeuy]*o[^aeiy]*u[^aeio]*y', w, re.I)

Answer 3

This is an optimal way to do it without having to use RegEx:

def verifyString(s):
    current_vowel = 'a'
    vowels= 'aeiouy'
    for c in s:
        if c==current_vowel:
            if len(vowels)==1:
                return True
            vowels = vowels[1:]
            current_vowel = vowels[0]
    return False

If you want the order to be strict, you can use:

def verifyStringStrict(s):
    current_vowel = 'a'
    vowels= 'aeiouy'
    for c in s:
        if c in vowels:
            if c==current_vowel:
                if len(vowels)==1:
                    return True
                vowels = vowels[1:]
                current_vowel = vowels[0]
            else:
                return False
    return False

You will have:

verifyString('saseqiqoqusyq') #True
verifyStringStrict('ssasdediqqodudyd') #True
verifyString('zazezizzudozyz') #False
verifyStringStrict('daezizzuzozyz') #False
verifyString('waewwiwuowuwcyd') #True
verifyStringStrict('waeiwuwowuwxyx') #False