Regex - Java - migrate a JS regex pattern to input of Java Pattern class

Question

I have following regex pattern working fine in Javascript :

Pattern-

/\<span\>(\d{2}-\d{2}-\d{4})\s*?(\d{1,2}:\d{2}\s*?(?:am|pm))\s*?(?:<\/SPAN><BR\/?><SPAN>)?\s*?((\d[ -]*?){13,17})\s*?\<\/span\>/i

String -

<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>

But I am getting an error when passing same pattern string to Pattern.compile() function .

Error is : Invalid escape sequence .

Here is what I tried :

Pattern p = Pattern.compile("/\<span\>(\d{2}-\d{2}-\d{4})\s*?(\d{1,2}:\d{2}\s*?(?:am|pm))\s*?(?:<\/SPAN><BR\/?><SPAN>)?\s*?((\d[ -]*?){13,17})\s*?\<\/span\>/i ");  

Matcher m = p.matcher("<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>");
boolean b = m.matches();

Please suggest how can i correct this .

Thanks

Edit

I changed my code to following after knowing comments, but now I cannot match the pattern:

Pattern p = Pattern.compile(
        "(?i)/\\<span\\>(\\d{2}-\\d{2}-\\d{4})\\s*?(\\d{1,2}:\\d{2}\\s*?(?:am|pm))\\s*?(?:<\\/SPAN><BR\\/?><SPAN>)?\\s*?((\\d[ -]*?){13,17})\\s*?\\<\\/span\\>");

Matcher m = p.matcher("<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>");
boolean b = m.matches();

System.out.println("Do regex pattern matches : " + b);

Double the backslashes, and replace the / at the start with (?i) and remove /i at the end. The rest is up to you to check. And avoid escaping / - it is not a special regex metacharacter. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Apr 10, 2017 at 10:46
but now I cannot match the pattern - Because there is / after (?i). Do not escape /, < and >. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Apr 10, 2017 at 10:57
thanks @WiktorStribiżew can you please tell from where i can learn more on this ? — Divyanshu Jimmy
– Divyanshu Jimmy, Commented Apr 10, 2017 at 11:04

wumpz · Accepted Answer · 2017-04-10 11:08:26Z

1

This one works. The only change derived from your edit was to remove the slash at the beginning. This was a simple JavaScript artifact.

Pattern p = Pattern.compile(
                "(?i)\\<span\\>(\\d{2}-\\d{2}-\\d{4})\\s*?(\\d{1,2}:\\d{2}\\s*?(?:am|pm))\\s*?(?:<\\/SPAN><BR\\/?><SPAN>)?\\s*?((\\d[ -]*?){13,17})\\s*?\\<\\/span\\>");
Matcher m = p.matcher("<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>");
boolean b = m.matches();
        System.out.println("Do regex pattern matches : " + b);

answered Apr 10, 2017 at 11:08

wumpz

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Comments

cнŝdk · Accepted Answer · 2017-04-10 11:10:48Z

1

You can use Pattern.CASE_INSENSITIVE field option to make your regex case insensitive instead of using (?i) flag in your regex:

Pattern p = Pattern.compile(
    "\\<span\\>(\\d{2}-\\d{2}-\\d{4})\\s*?(\\d{1,2}:\\d{2}\\s*?(?:am|pm))\\s*?(?:<\\/SPAN><BR\\/?><SPAN>)?\\s*?((\\d[ -]*?){13,17})\\s*?\\<\\/span\\>",
Pattern.CASE_INSENSITIVE);

Matcher m = p.matcher("<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>");

System.out.println("Do regex pattern matches : " + m.matches());

Note:

And also as mentioned in comments in Java you don't need to wrap your regex between slaches /, you need to update your regex string and remove the leading / from it and it will work as expected.

This is a working Demo.

edited Apr 10, 2017 at 11:10

answered Apr 10, 2017 at 10:58

cнŝdk

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2 Comments

Divyanshu Jimmy Over a year ago

its not able to match either ways .

cнŝdk Over a year ago

@Softxide You will need to update your regex string and remove the leading /, see my Edit.

JUAN CALVOPINA M · Accepted Answer · 2017-04-10 11:12:23Z

1

You should remove the first / character and use Pattern.CASE_INSENSITIVE. For example:

String regex = "\\<span\\>(\\d{2}-\\d{2}-\\d{4})\\s*?(\\d{1,2}:\\d{2}\\s*?(?:am|pm))\\s*?(?:<\\/SPAN><BR\\/?><SPAN>)?\\s*?((\\d[ -]*?){13,17})\\s*?\\<\\/span\\>";

Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);

Matcher m = p.matcher("<SPAN>06-24-2015  11:28AM  0250 01 90775 05342</SPAN>");
boolean b = m.matches();
System.out.println("result: "  + b);

Output:

result: true

answered Apr 10, 2017 at 11:12

JUAN CALVOPINA M

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