# About String.sub

**URL:** <https://www.ruby-forum.com/t/about-string-sub/148183>\
**Category:** Ruby\
**Created:** [September 10, 2008, 4:29am UTC](https://www.ruby-forum.com/t/about-string-sub/148183 "2008-09-10T04:29:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Kyung\_won\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/47e85d/32.png) [@Kyung\_won\_C](https://www.ruby-forum.com/u/Kyung_won_C)\
**Post date:** [September 10, 2008, 4:29am UTC](https://www.ruby-forum.com/t/about-string-sub/148183/1 "2008-09-10T04:29:56Z")

</div>

in javascript

var str = “aaa(xxx)bbb”  
str.replace(/aaa((.+))bbb/, ‘AAA(’ + ‘$1’ + ‘)BBB’) // “AAA(xxx)BBB”

in ruby

How???

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<div class="post-metadata">

**Author:** ![Kyung\_won\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/47e85d/32.png) [@Kyung\_won\_C](https://www.ruby-forum.com/u/Kyung_won_C)\
**Post date:** [September 10, 2008, 5:49am UTC](https://www.ruby-forum.com/t/about-string-sub/148183/2 "2008-09-10T05:49:20Z")

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From: Kyung won Cheon [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)]

# in javascript

# var str = “aaa(xxx)bbb”

# str.replace(/aaa((.+))bbb/, ‘AAA(’ + ‘$1’ + ‘)BBB’) //

```
                         watch out ^^^^

```

# “AAA(xxx)BBB”

# in ruby How???

see [class String - RDoc Documentation](http://ruby-doc.org/core/classes/String.html#M000831)

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<div class="post-metadata">

**Author:** ![Kyung\_won\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/47e85d/32.png) [@Kyung\_won\_C](https://www.ruby-forum.com/u/Kyung_won_C)\
**Post date:** [September 10, 2008, 10:48am UTC](https://www.ruby-forum.com/t/about-string-sub/148183/3 "2008-09-10T10:48:59Z")

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Kyung won Cheon wrote:

> in javascript
> 
> var str = “aaa(xxx)bbb”  
> str.replace(/aaa((.+))bbb/, ‘AAA(’ + ‘$1’ + ‘)BBB’) // “AAA(xxx)BBB”
> 
> in ruby
> 
> How???

str.sub!(/aaa((.+))bbb/){‘AAA(’ + $1 + ‘)BBB’}

TPR