不区分大小写的 String split() 方法

Question

When I perform

String test="23x34 ";
String[] array=test.split("x"); //splitting using simple letter

I got two items in array as 23 and 34

but when I did

String test="23x34 ";
String[] array=test.split("X"); //splitting using capitalletter

I got one item in array 23x34

So is there any way I can use the split method as case insensitive or whether there is any other method that can help?

Answer 1

split uses, as the documentation suggests, a regexp. a regexp for your example would be :

"[xX]"

Also, the (?i) flag toggles case insensitivty. Therefore, the following is also correct :

"(?i)x"

In this case, x can be any litteral properly escaped.

Answer 2

Use regex pattern [xX] in split

String x = "24X45";
String[] res = x.split("[xX]");
System.out.println(Arrays.toString(res));

Answer 3

您还可以在正则表达式中使用嵌入式标志：

String[] array = test.split("(?i)x"); // splits case insensitive

Answer 4

I personally prefer using

String modified = Pattern.compile("x", Pattern.CASE_INSENSITIVE).matcher(stringContents).replaceAll(splitterValue);
String[] parts = modified.split(splitterValue);

In this way you can ensure any regex will work, as long as you have a unique splitter value

Answer 5

In addition to the existing answers, you can use Pattern.CASE_INSENSITIVE flag to convert your regex pattern into a case-insensitive pattern which you can directly use to split your string eg

String[] arr = Pattern.compile("x", Pattern.CASE_INSENSITIVE).split("23x34 ");

Demo:

import java.util.Arrays;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        Pattern pattern = Pattern.compile("x", Pattern.CASE_INSENSITIVE);
        
        System.out.println(Arrays.toString(pattern.split("23x34 ")));
        System.out.println(Arrays.toString(pattern.split("23X34 ")));
    }
}

Output:

[23, 34 ]
[23, 34 ]

Answer 6

For JavaScript:

var test="23x34 ";
var array = test.split(\x\i);

Answer 7

Java's String class' split method also accepts regex.

To keep things short, this should help you: http://www.coderanch.com/t/480781/java/java/String-split

Answer 8

It's a bit complex, but here's how it could be implemented:

1. Lowercase both the strings (overall text and search term)
2. Run the text.split(searchTerm)
3. This gives you an array of strings that are NOT search terms
4. By walking through this array, you're getting lengths of each of these strings
5. Between each of those strings, there must be a search term (with known length)
6. By figuring out indexes, you can now .slice() the pieces from the original string

Answer 9

You could use a regex as an argument to split , like this:

"32x23".split("[xX]");

Or you could use a StringTokenizer that lets you set its set of delimiters, like this:

StringTokenizer st = new StringTokenizer("32x23","xX");
//                                          ^^    ^^
//                                       string delimiter

This has the advantage that if you want to build the list of delimiters programatically, for example for each lowercase letter in the delimiter list add its uppercase corespondent, you can do this and then pass the result to the StringTokenizer .