how to replace string with different replacement in java

Question

Now I have a String like this

it is #1, or #2, or #3

I want to transfer it to this:

it is < a href="/1">#1< /a>, or #< a href="/2">#2< /a>, or < a href="/3">#3< /a>

So I want to replace the word "#{num}" to "< a href="/{num}">#{num}< /a>"

What shall I do?

Do you want href="/1" in all 3 cases?

anubhava
– anubhava

2014-09-16 07:29:18 +00:00
Commented Sep 16, 2014 at 7:29 — anubhava
– anubhava, Commented Sep 16, 2014 at 7:29
sorry, I modified it now

xierui
– xierui

2014-09-16 07:31:17 +00:00
Commented Sep 16, 2014 at 7:31 — xierui
– xierui, Commented Sep 16, 2014 at 7:31
Thanks for update, posted an answer with demo.

anubhava
– anubhava

2014-09-16 07:34:51 +00:00
Commented Sep 16, 2014 at 7:34 — anubhava
– anubhava, Commented Sep 16, 2014 at 7:34

anubhava · Accepted Answer · 2014-09-16 07:34:27Z

2

This Java code should work:

String repl = input.replaceAll("(?<!>)#(\\d+)(?!<)", "<a href=\"/$1\">#$1</a>");

RegEx Demo

PS: I have added lookaheads to make sure we don't replace a string with hyperlinks like: it is <a href="/1">#1</a> (check demo link for an example).

answered Sep 16, 2014 at 7:34

anubhava

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Boris the Spider Over a year ago

+1. I was thinking of doing this then decided to go down the Matcher.appendReplacement route - can't quite remember why. This is much shorter!

Avinash Raj · Accepted Answer · 2014-09-16 07:37:37Z

1

Use capturing group to capture the # along with the following number.

Regex:

(#(\\d+))

Replacement string:

< a href="/$2">$1< /a>

DEMO

String str = "it is #1, or #2, or #3";
System.out.println(str.replaceAll("(#(\\d+))", "< a href=\"/$2\">$1< /a>"));

Output:

it is < a href="/1">#1< /a>, or < a href="/2">#2< /a>, or < a href="/3">#3< /a>

edited Sep 16, 2014 at 7:37

answered Sep 16, 2014 at 7:28

Avinash Raj

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2 Comments

xierui Over a year ago

sorry, but i want the string to be < a href="/{num}">#{num}< /a>

xierui Over a year ago

thank you for your answer , it is my fault. I am sorry

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