Java, string arrays. Checking the text if the first and last letter are same. I need to do it in regular expr

Question

I have some text , i separated the words and now I need to check each word if it starts with the same letter it ends ( example: 'teeet','teeeT,'Teeet'). How do i do that ? Here is what I've done:

    Scanner input = new Scanner(System.in);
    String text = input.nextLine();

    String[] arr = text.split(" ");
    System.out.println("Display all words in a string: ");
    for ( String ss : arr) {

        // What now ?
    }

I need to do it in regular expression

Scanner already splits by space if you use `next()` – Peter Lawrey Oct 13 '13 at 13:57 — Peter Lawrey, Oct 13 '13 at 13:57

score 4 · Answer 1 · edited May 23 '17 at 10:25

4

You can use String#charAt and String#length:

char first = ss.charAt(0);
char last  = ss.charAt(ss.length() - 1);

Now compare them.

I recommend you to always check the docs before asking, it will contain the answer for questions like this.

For your edit, see this answer by @Bohemian:

you can determine using regex if the first and last characters are the same:

str.matches("(.).*\\1")

edited May 23 '17 at 10:25

Community

1
1

answered Oct 13 '13 at 13:51

Maroun

94,125
30
188
241

score 3 · Answer 2 · answered Oct 13 '13 at 13:52

3

if (ss.charAt(0) == ss.charAt(s.length() - 1)) {
    // Do your stuff
}

answered Oct 13 '13 at 13:52

ssantos

16,001
7
50
70

Bohemian · Accepted Answer · 2013-10-13T14:13:22.183

2

Use regex:

if (str.matches("(?i)(.).*\\1"))

edited Oct 13 '13 at 14:13

answered Oct 13 '13 at 14:02

Bohemian

412,405
93
575
722

But how do I do the same but if the first letter is uppercase and last is lowercase ? So 'Teeet' and 'teeeT' would also be true ? – user2706783 Oct 13 '13 at 14:12
I've added the "ignore case" switch `(?i)` to the regex - it will work as you need now. – Bohemian Oct 13 '13 at 14:13

score 0 · Answer 4 · answered Oct 13 '13 at 14:09

package test;

import java.util.Scanner;

public class Test {

public static void main(String[] args) {
    new Test();
}

public Test() {
    Scanner input = new Scanner(System.in);
    String text = input.nextLine();

    String[] arr = text.split(" ");
    System.out.println("Display all words in a string: ");
    for (String ss : arr) {
        System.out.println("testing word:" + ss);
        String firstLetter = ss.substring(0, 1);
        String lastLetter = ss.substring(ss.length() - 1, ss.length());
        boolean firstEqualsLast = firstLetter.equalsIgnoreCase(lastLetter);
        System.out.println("first char equals last char=" + firstEqualsLast);
    }
}
}

Java, string arrays. Checking the text if the first and last letter are same. I need to do it in regular expr

4 Answers4