Splitting String using split method

Question

I want split a string like this:

  C:\Program\files\images\flower.jpg

but, using the following code:

  String[] tokens = s.split("\\");
  String image= tokens[4];

I obtain this error:

 11-07 12:47:35.960: E/AndroidRuntime(6921): java.util.regex.PatternSyntaxException: Syntax error U_REGEX_BAD_ESCAPE_SEQUENCE near index 1:

But I want split the Original String in 5 parts: C: Program files images flower.jpg — GVillani82, Nov 07 '12 at 11:56
duplicate http://stackoverflow.com/questions/4025482/cant-escape-the-backslash-with-regex — Bhavik Shah, Nov 07 '12 at 12:00

PermGenError · Accepted Answer · 2012-11-07T12:10:23.137

5

try

String s="C:\\Program\\files\\images\\flower.jpg"

String[] tokens = s.split("\\\\");

In java(regex world) \ is a meta character. you should append with an extra \ or enclose it with \Q\E if you want to treat a meta character as a normal character.

below are some of the metacharacters

<([{\^-=$!|]})?*+.>

to treat any of the above listed characters as normal characters you either have to escape them with '\' or enclose them around \Q\E

like:

        \\\\ or \\Q\\\\E

edited Nov 07 '12 at 12:10

answered Nov 07 '12 at 11:55

PermGenError

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@Joseph82, the reason it works is because a Regex pattern starts and ends with the \ sign, and you need to escape the special char \ so you start and end the pattern with the \ sign, and then the pattern itself is the special char (with escaping) \\. all in all it's \\\\ – thepoosh Nov 07 '12 at 12:05

score 2 · Answer 2 · answered Nov 07 '12 at 11:57

You need to split with \\\\, because the original string should have \\. Try it yourself with the following test case:

    @Test
public void split(){
      String s = "C:\\Program\\files\\images\\flower.jpg";     


        String[] tokens = s.split("\\\\");
        String image= tokens[4];
        assertEquals("flower.jpg",image);
}

score 1 · Answer 3 · answered Nov 07 '12 at 11:57

There is 2 levels of interpreting the string, first the language parser makes it "\", and that's what the regex engine sees and it's invalid because it's an escape sequence without the character to escape.

So you need to use s.split("\\\\"), so that the regex engine sees \\, which in turn means a literal \.

If you are defining that string in a string literal, you must escape the backslashes there as well:

String s = "C:\\Program\\files\\images\\flower.jpg";

score 1 · Answer 4 · answered Nov 07 '12 at 12:01

1

String[] tokens=s.split("\\\\");

answered Nov 07 '12 at 12:01

Venkatesh S

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score 1 · Answer 5 · answered Nov 07 '12 at 12:03

1

Try this:

String s = "C:/Program/files/images/flower.jpg";
String[] tokens = s.split("/");
enter code hereString image= tokens[4];

answered Nov 07 '12 at 12:03

Shahinoor Shahin

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score 0 · Answer 6 · answered Nov 07 '12 at 11:55

0

Your original input text should be

 C:\\Program\\files\\images\\flower.jpg

instead of

 C:\Program\files\images\flower.jpg

answered Nov 07 '12 at 11:55

Ahmad

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I get the String from a web service. So I insert the path in the string in this way (using Ksoap2): s = response.getProperty("image").toString(); – GVillani82 Nov 07 '12 at 12:09

score 0 · Answer 7 · answered Nov 07 '12 at 12:03

This works,

    public static void main(String[] args) {
        String str = "C:\\Program\\files\\images\\flower.jpg";
        str = str.replace("\\".toCharArray()[0], "/".toCharArray()[0]);
        System.out.println(str);
        String[] tokens  = str.split("/");
        System.out.println(tokens[4]);      
    }

Splitting String using split method

7 Answers7