java.util.regex.PatternSyntaxException: null (in java.util.regex.Pattern) error

Question

public void convertStrings() {
    for (int counter = 0; counter < compare.length; counter++) {
            compare[counter] = compare[counter].replace('*','_'); 
            compare[counter] = compare[counter].replaceAll("_",".*"); 
            compare[counter] = compare[counter].replace('?', '.'); 
    }
    // System.out.printf("%s", Arrays.toString(compare));
} 
public void compareStrings() {
    for (int counter = 0; counter < data.length; counter++) {
        for (int counter1 = 0; counter1 < compare.length; counter1++) {

            if (data[counter].matches(compare[counter1]) == true) {
                System.out.printf("%s ", data[counter]); 
            }

        }
        System.out.println(); 
    }
}

}

what i'm trying to do is replace any * in my input to a .* so that when i compare the string to anything before, it'll ignore previous characters. Also, i'm converting a "?" into a placeholder value ".". However, when i run the compiled code, I get this error because the string converts the special characters into regular letters. How do i make the compiler register these special characters to perform the function?

Will · Accepted Answer · 2011-02-07 02:04:00Z

1

Just change the lines to:

compare[counter] = compare[counter].replaceAll("\\*",".*").replaceAll("\\?", ".");

answered Feb 7, 2011 at 2:04

Will

6,2964 gold badges33 silver badges49 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Paul Wagland · Accepted Answer · 2011-02-07 02:15:19Z

0

I am assuming that the error is being thrown from the line

if (data[counter].matches(compare[counter1]) == true)

If so, the most likely explanation is that compare[counter1] is actually null, that is it does not contain a value.

answered Feb 7, 2011 at 2:15

Paul Wagland

29.4k10 gold badges55 silver badges75 bronze badges

Collectives™ on Stack Overflow

java.util.regex.PatternSyntaxException: null (in java.util.regex.Pattern) error

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related