Java: Extract characters from string
Sometimes you need to get one character from a string. For example, if the site knows the user's first and last name, and at some point you need to display this information in the format A. Ivanov
, then you need to take the first character from the name.
var firstName = "Alexander";
System.out.print(firstName.charAt(0)); // => A
charAt(int index) is a special method for extracting a character from a string. Index is the position of the character within the string. Indices start with 0 in almost all programming languages - therefore, to get the first character, you need to specify the index 0
.
An index can be not only a specific number, but also the value of a variable. Here is an example that will lead to the same result - displaying the A
symbol on the screen, but the index inside the round brackets is written not by a number, but by a variable:
var firstName = "Alexander";
var index = 0;
System.out.print(firstName.charAt(index)); // => A
Although the character is not a string, the concatenation operation (+) can work if one of the arguments is a character. It will make a string of it and compute it as a concatenation of two strings. But don't try to concatenate characters with each other, not with a string - the Java compiler will decide that you want to add the numeric codes of these characters, and the result will be some number.
System.out.print('H' + 'A'); // => 137
System.out.print('H' + " " + 'A'); // => "H A"
Instructions
You are given three variables with the names of different people. Compose and display a word of characters in this order:
- the third character from the first line;
- the second character from the second line;
- the fourth character from the third line;
- the fifth character from the second line;
- the third character from the second line.
The output should be something like this: "a b c d e"