来自拆分字符串问题的数组

Question

Hello I am using the following java code to split user input into individual words -

String command = scanner.next();
command = command.toLowerCase();
String[] words = command.split(" ");

• however when i try to print " words[1] " for an input with two or more words it throws a ArrayIndexOutOfBoundsException. It would seem that words[1] would simply be the second word in the sentence but the array does not contain it.

Answer 1

Instead of scanner.next() , try

String command = scanner.nextLine();

This will make sure you read all the words.

Answer 2

From the Scanner API :

A Scanner breaks its input into tokens using a delimiter pattern, which by default matches whitespace.

While the javadoc for Scanner#next() states:

Finds and returns the next complete token from this scanner. A complete token is preceded and followed by input that matches the delimiter pattern.

So in your case scanner.next() will return a word with no whitespace , as whitespace is how your scanner likely knows when to stop scanning.

You might want to use Scanner#nextLine() or something of the sort instead.

Answer 3

Try this one, and make sure you have read all input words

Scanner scanner = Scanner(System.in);
String command = scanner.nextLine();
command = command.toLowerCase();
String[] words = command.split(" ");

Now you can print

words[1]

if you have valid index value,