Clever Geek Handbook

Extracting number in java string

I have a pretty simple question: I have line 0-1000 let's say str = "0-1000"

I am successfully fetching 0 and 1000 with str.split("-")

I am now tasked with checking the number because I noticed that these two numbers can be negative.

If I continue str.split("-")

, I will also miss the negative sign.

Can anyone suggest me methods?

+3


source to share


2 answers


Since it String.split()

uses regular expressions for separation, you can do something like this:

String[] nos = "-1000--1".split("(?<=\\d)-";

This means that you are separating the minus characters that follow the digit, i.e. must be the operator.



Note that you need to use a positive look-behind (?<=\d)

as you only want to match the minus character. String.split()

removes all matching delimiters and thus something like \d-

removes digits as well.

To parse the numbers you then iterate over the elements of the array and call Integer.valueOf(element)

or Integer.parseInt(element)

.

Note that this assumes the input string is valid. Depending on what you want to achieve, you first need to check the input to match, eg. using -?\d--?\d

to check if a string is in a format x-y

where x

and y

can be positive or negative integers.

+4


source


You can use regex like this: Works for all cases

public static void main(String[] args) {
    String s = "-500--578";
    String[] arr = s.split("(?<=\\d)-"); // split on "-" only if it is preceeded by a digit
    for (String str : arr)
        System.out.println(str);
}


O / P:

-500
-578
+4


source






More articles:


All Articles