In Java how do you randomly select a letter (a-z)?

Question

If I want to randomly select a letter between a and z, I assume I have to use the Random class:

Random rand = new Random();

But since this only generates numbers, what do I need to do to apply this to letters?

Answer 1

Random r = new Random();
char c = (char) (r.nextInt(26) + 'a');

Answer 2

Letters, or more exactly, characters, are numbers (from 0 to 255 in extended ascii, 0 to 127 in non-extended). For instance, in ASCII, 'A' (quote means character, as opposed to string) is 65. So 1 + 'A' would give you 66 - 'B'. So, you can take a random number from 0 to 26, add it to the character 'a', and here you are : random letter.

You could also do it with a string, typing "abcdefghijklmnopqrstuvwxyz" and taking a random position in this chain, but Barker solution is more elegant.

Answer 3

alter version of @Michael Barker

    Random r = new Random();
    int c = r.nextInt(26) + (byte)'a';
    System.out.println((char)c);

Answer 4

char randomLetter = (char) ('a' + Math.random() * ('z'-'a' + 1));

Answer 5

why assume to use Random instead of Math.random? You can even make the code shorter...

public static char genChar(){
    return (char)(Math.random()*26 + 'a');
}

Answer 6

import static org.apache.commons.lang3.RandomStringUtils.randomAlphabetic;
...
randomAlphabetic(1).toLowerCase()

this gives you a string with single character

Answer 7

To randomly select a letter from (a- z) I would do the following:

Random rand = new Random();
...
char c = rand.nextInt(26) + 'a';

Since Random.nextInt() generates a value from 0 to 25, you need only add an offset of 'a' to produce the lowercase letters.

Answer 8

使用字母的 ascii 值生成随机数。

Answer 9

Random r = new Random();
char symbel = (char)(r.nextInt(26) + 'a');
if(symbel>='a' && symbel <= 'z') {
    System.out.println("Small Letter" + symbel);
} else {
    System.out.println("Not a letter" + symbel);
}