CODEWITHSUNDEEP
javaregex
StackOverFlow
StackOverFlow

Reputation: 4614

Regular expression for Custom Decimal

My definition of Custom Decimal => The number can be represented as (p,s) where p is the precision and s is the scale and then describe everything with respect to precision and scale. Use Custom Decimal if you need to store decimals that have more than eight digits in the fractional part. Can have a maximum scale of 29 and a maximum precision of 30. The non-fractional part of the number can have a maximum of 29 digits.

P and S may vary...

Assume P= 18 S=12 i.e/ (P,S) = (18,12)

intLength = 12

fractionalLength=18

Piece of code

String regExprCD = "^-?\\d{1,"+intLength+"}(?>\\.\\d{0,"+fractionalLength+"})?$";

                    info("regExprCD = "+regExprCD );
                    if (value.matches(regExprCD ) || value.isEmpty()){
                        Window.alert("Valid CUSTOM_DECIMAL value");
                    }else{
                        Window.alert("Valid CUSTOM_DECIMAL value");
                    }

I tried following regular Expression but error comes on page "Syntax error in regular expression"

^-?\\d{1,"+intLength+"}(?>\\.\\d{0,"+fractionalLength+"})?$

Which is perfect regular expression to allow following cases :

Regular expression should accept following Custom Decimal:

123456789012345678

1234567.1234567890

1.123456789012

1234567890.1234567

12345678901234567.

12345.

Regular expression should not accept following Custom Decimal:

12345678901234567890 : Reason P > 18 :: P should not be greater than 18

1234567.1234567890123 : Reason s>12 : :: S should not be greater than 12

.1 or .1232 :: Invalid

I used ^-?\\d{1,"+intLength+"}(?>\\.\\d{0,"+fractionalLength+"})?$ this regular expression.

This regular expression working fine in Sample java program. Not working in GWT

Throwing error on web page (developed in GWT) :: "Syntax error in regular expression"

what should be data type of intLength and fractionalLength ? int or string ?

Which is perfect regular expression ?

Any help or guidance in this matter would be appreciated.

Upvotes: 2

Views: 1759

Answers (2)

user3759153
user3759153

Reputation: 1

Try : ^[\d]{1,3}[.]{1}[\d]{1,1}|^[\d]{1,3}

public class RegexTestStrings {
    public static void main(String[] args) {
        String[] EXAMPLE_TEST = {"123", "0", "123.4", ".1", "123.", "12a", "a12"};
        int P= 4, S=1;
        for(int i = 0; i< EXAMPLE_TEST.length; i++){
            System.out.println(EXAMPLE_TEST[i]+" -- "+EXAMPLE_TEST[i].matches("^[\\d]{1,"+(P-S)+"}[.]{1}[\\d]{1,"+(S)+"}|^[\\d]{1,"+(P-1)+"}"));    
        }
    }
}

Result : 

123 -- true
0 -- true
123.4 -- true
.1 -- false
123. -- false
12a -- false
a12 -- false

Upvotes: 0

Thomas
Thomas

Reputation: 88707

You could try this expression: ^-?\d{0,x}(?>\.\d{0,y})?$ which should match any number starting with an optional minus, then up to x digits, followed by a dot and up to y digits.

x and y would be your intLength and fractionalLength.

If you want to make the integer or fraction part a requirement (such that .1 or 1. don't match), just replace the zero in the number interval with a 1, i.e. ^-?\d{1,x}(?>\.\d{1,y})?$.

Update:

Here's a SSCCE with fixed lengths:

String expression = "^-?\\d{1,18}(?>\\.\\d{0,12})?$";

//prints true
System.out.println("12345678".matches(expression)); 

//prints true
System.out.println("1234.5678".matches(expression)); 

//prints false -> integer part too long
System.out.println("1234567890123456789.5678".matches(expression)); 

//prints false -> fraction part too long
System.out.println("1234.1234567890123".matches(expression)); 

//prints false -> integer part missing
System.out.println(".5678".matches(expression));

Upvotes: 2

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