CODEWITHSUNDEEP
pythonpython-2.7slice
lookininward
lookininward

Reputation: 671

How can I capture characters in a string up to the first vowel and create substring out of it?

Currently, the first part of my code works correctly. If it detects that the first character (index 0) is a vowel it stops and adds "yay" to the end of word.

The second part is intended to capture consonants up to the first vowel. This works correctly.

The problem occurs when I try to take the original word and slice off everything up to the first vowel and create a new substring out of it. This would mean that if the user inputs "hello" it should output "ellohay". I can get "hellohay" but can't figure out how to capture those initial consonants and slice them out.

# 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()

Upvotes: 2

Views: 2355

Answers (3)

Padraic Cunningham
Padraic Cunningham

Reputation: 180542

if you want to drop all leading chars until you hit a vowel you can use 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")

output: ellohay

lambda x: x not in vowels means we want to drop all chars until we find a character in vowels. If you want to work for upper or lowercase add the uppercase vowels to the set or switch the lambda to x.lower() not in vowels

Upvotes: 2

Vaibhav Aggarwal
Vaibhav Aggarwal

Reputation: 1411

Using regex would probably be your best bet:

# 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()

This basically non-greedily searches the string until it hits a vowel, and makes two groups of the consonants and the vowel+following string, and manipulates them accordingly. 

$ 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

Upvotes: 2

Eugene Primako
Eugene Primako

Reputation: 2817

This code looks rather strange. For instance, the second if i in vowels: is never reached.

Instead of this you may want to:

  1. Find the position of first vowel - let it be pos
  2. check if pos > 0
  3. return user_input[pos:] + user_input[:pos-1] + 'ay'

Upvotes: 0

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