CODEWITHSUNDEEP
javastringsearchindexof
user3033159
user3033159

Reputation: 17

Search a string for multiple letters at once

I need to search a string for vowels at the end of a four letter word. I could do an if-else tree and search each letter individually, but I would like to simplify.

You generally search for a letter by this way:

String s = four
if (s.indexOf ('i') = 4)
  System.out.println("Found");
else
  System.out.println("Not found");

Could I instead replace the parameter of the indexOf with this:

s.indexOf ('a','e','i','o','u')

It would make everything a lot easier.

Unfortunately, I cannot use Regexp classes, and I'm required to only use things we have previously learned.

Upvotes: 2

Views: 6909

Answers (4)

user1019830
user1019830

Reputation:

This is a job for String#matches(String) and a suiting regular expression:

if (s.matches(".*[aeiou]$")) {
    /* s ends with a vowel */
}

If using regular expressions is not allowed you could define a function for this:

static boolean endsWithVowel(String str) {
    if (str == null || str.length() == 0) {  /* nothing or empty string has no vowels */
        return false;
    }
    return "aeiou".contains(str)             /* str is only vowels */
        || endsWithVowel(str.substring(1));  /* or rest of str is only vowels */
}

Upvotes: 0

MadConan
MadConan

Reputation: 3767

Regex? I believe this works. "Any 3 word characters followed by a e i or u."

    Pattern p = Pattern.compile("\\w{3}[aeiou]?");
    String test = "mike";
    System.out.println("matches? " + p.matcher(test).matches());

Well, if you can't use regex, then use why not something like EDIT: Modified to be inline with GaborSch's answer -- my alternate algorithm was very close, but the use of the char instead of creating another string is WAY better! Give an upvote to GaborSch!)

    if(someString.length() == 4){
        char c = someString.charAt(3);

        if("aeiou".indexOf(c) != -1){
             System.out.println("Gotcha ya!!");
        }
    }

Upvotes: 3

gaborsch
gaborsch

Reputation: 15758

Try this way:

char c = s.charAt(3);
if("aeiou".indexOf(c) >= 0) {
    System.out.println("Found");
} else {
    System.out.println("Not found");
}

The trick is that you pick the 4th character and search for it in the String of all vowels.

This is a Regexp-free one-liner solution.

Upvotes: 1

Saj
Saj

Reputation: 18712

String s = "FOUR"; // A sample string to look into
String vowels = "aeiouAEIOU"; // Vowels in both cases

if(vowels.indexOf(s.charAt(3)) >= 0){ // The last letter in a four-letter word is at index 4 - 1 = 3
    System.out.println("Found!");
} else {
    System.out.println("Not Found!");
}

Upvotes: 3

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