How to extract substring from a string using regex?

Question

I want to extract the user name and the date from the following string:

Syed Arafath on Jan 7, 2015
Capt.KSD on Dec 30, 2014
chakradharalasakani on Dec 29, 2014
mitesh0123 on Dec 18, 2014
Aparajita61@yahoo.in on Dec 3, 2014
123chetan on Oct 28, 2014

I want the output as follows:

Syed Arafath
Capt.KSD
chakradharalasakani
mitesh0123
Aparjita61@yahoo.co.in
Jan 7,2015
Dec 30, 2014
Dec 29,2014
Dec 18,2014
Dec 3, 2014
Oct 28, 2014

In all I want to split the string "Syed Arafath on Jan 7, 2015" into 2 strings, one containing the username and the other containing the date.

possible duplicate of [Learning Regular Expressions](http://stackoverflow.com/questions/4736/learning-regular-expressions) — Andy Brown, Jan 16 '15 at 13:31

vks · Answer 1 · 2015-01-16T13:26:04.700

4

Do a split on \\s+on\\s+ and you should get what you want

See demo.

https://regex101.com/r/tX2bH4/29

EDIT:

use \\s+on\\s+(?!.*\bon\b)

https://regex101.com/r/tX2bH4/30

If you care about Syed on Arafath too.The lookahead makes sure split occurs on the last on .

edited Jan 16 '15 at 13:26

answered Jan 16 '15 at 13:19

vks

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1

What if `Syed Arafath`'s name was instead `Syed on Arafath`? – blgt Jan 16 '15 at 13:21
1

you need to use `\\s+` – Avinash Raj Jan 16 '15 at 13:28
carefull with the `on` inside the lookahead.. – Avinash Raj Jan 16 '15 at 13:30

Avinash Raj · Answer 2 · 2015-01-16T13:26:32.150

1

Just split your input according to the below regex,

"\\s+on\\s+(?=\\S+\\s+\\d{1,2},)"

Code:

String txt = "Syed on Arafath on Jan 7, 2015";
String[] parts = txt.split("\\s+on\\s+(?=\\S+\\s+\\d{1,2},)");
System.out.println(Arrays.toString(parts));

Output:

[Syed on Arafath, Jan 7, 2015]

edited Jan 16 '15 at 13:26

answered Jan 16 '15 at 13:20

Avinash Raj

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score 0 · Accepted Answer · answered Jan 16 '15 at 13:27

0

import java.util.regex.*;
Pattern p = Pattern.compile("(.*) on (.*)");
Matcher m = p.matches(input);
if( m.matches() ) {
    String username = m.group(1);
    String date = m.group(2);
} else {
    throw new Exception("Did not match expected pattern");
}

answered Jan 16 '15 at 13:27

Nicholas Daley-Okoye

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score 0 · Answer 4 · answered Jan 16 '15 at 13:29

Using a direct regex is preferrable to splitting:

Matcher m = Pattern.compile("(.*) on .*").matcher(input);
m.matches();
System.out.println(m.group(1));

The greedy quality of the * quantifier guarantees that any occurrence of on within the name will be grabbed by it and only the last occurence of on will be matched by the on literal.

score 0 · Answer 5 · answered Jan 16 '15 at 13:29

0

As an alternative to split you can use replaceAll

    String name = s.replaceAll("(.*) on .*", "$1");
    String date = s.replaceAll(".*(\\w{3} \\d{1,2}, \\d{4}).*", "$1");

answered Jan 16 '15 at 13:29

Evgeniy Dorofeev

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How to extract substring from a string using regex?

5 Answers5