How to get a substring of a certain character followed by a number?

Question

In Java, how would I get a substring of a certain character followed by a number?

The string looks like this:

To be, or not to be. (That is the question.) (243)

I want the substring up until the (243), where the number inside the parenthesis is always changing every time I call.

Could there be numbers elsewhere in the string? – PurpleVermont Jan 20 '14 at 20:13 — PurpleVermont, Jan 20 '14 at 20:13
You mean the regular expression `$(\d+)$`? – chrylis -cautiouslyoptimistic- Jan 20 '14 at 20:13 — chrylis -cautiouslyoptimistic-, Jan 20 '14 at 20:13

score 2 · Accepted Answer · answered Jan 20 '14 at 20:34

2

Use a regular expression:

newstr = str.replaceFirst("\(\d+\)", "");

What this means is to find a substring beginning with (, then any number of digits, and then the character ). Then replace the substring with the empty string, "".

Reference: java.lang.String.replaceFirst()

answered Jan 20 '14 at 20:34

i-bob

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5

I didn't realize that the String class had built-in methods (in this case called replaceFirst) that recognized a regular expressions. This is the answer I was really looking for. – djangofan Jan 20 '14 at 20:49
I think you might want to anchor your regular expression to the end of the line using $ in case there happens to be a parenthesized number in your string, like `There are four (4) lights! (345)` – PurpleVermont Jan 21 '14 at 03:02

score 0 · Answer 2 · edited May 23 '17 at 10:31

0

You could match it with a regex, and get the index of the regex. Then use that to get the index in the string.

An example of that is Can Java String.indexOf() handle a regular expression as a parameter?

Pattern pattern = Pattern.compile(patternStr);
Matcher matcher = pattern.matcher(inputStr);
if(matcher.find()){
    System.out.println(matcher.start());//this will give you index
}

edited May 23 '17 at 10:31

Community

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1

answered Jan 20 '14 at 20:14

Jeff Storey

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I'll try this. Thanks, it looks like the answer. – djangofan Jan 20 '14 at 20:15

score 0 · Answer 3 · answered Jan 20 '14 at 20:16

0

You can use String.replaceAll():

String s = "To be, or not to be. (That is the question.) (243)";
String newString = s.replaceAll("\\(\\d+\\).*", "");

answered Jan 20 '14 at 20:16

Keppil

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score 0 · Answer 4 · answered Jan 20 '14 at 20:18

0

I think you can actually just do something like:

mystring.substring(0,mystring.lastIndexOf"("))

assuming that the last thing on the line will be the number in parentheses.

answered Jan 20 '14 at 20:18

PurpleVermont

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I'm not sure if you need to escape the `(` in quotes there or not -- you could also specify it as a `char` rather than a string, which may be more efficient too. – PurpleVermont Jan 20 '14 at 20:19

score 0 · Answer 5 · answered Jan 20 '14 at 20:22

You could use a for loop and add the characters before the number to a separate string

String sentence = "To be, or not to be. (That is the question.) (243)";

public static void main(String[] args) {
    String subSentence = getSubsentence(sentence);
}

public String getSubsentence(String sentence) {
    String subSentence = "";
    boolean checkForNum = false;
    for (int i = 0; i < sentence.length(); i++) {
        if (checkForNum) {
            if (isInteger(sentence.getSubstring(i, i+1))) return subSentence;
            checkForNum = false;
        } else {
            if (sentence.getSubstring(i, i+1).equals("(")) checkForNum = true;
            else subSentence += sentence.getSubstring(i, i+1);
        }
    }
    return subSentence;
}

public boolean isInteger(String s) {
try { 
    Integer.parseInt(s); 
} catch(NumberFormatException e) { 
    return false; 
}
    return true;
}

score 0 · Answer 6 · answered Jan 20 '14 at 20:39

Using a regex this can be solved with.

public class RegExParser {

    public String getTextPart(String s) {

        String pattern = "^(\\D+)(\\s\\(\\d+\\))$";

        String part = s.replaceAll(pattern, "$1");
        return part;

    }
}

Simple and performance is good.

How to get a substring of a certain character followed by a number?

6 Answers6