How to get placeholder from string in Javascript?

Question

I have a string with one or more placeholders in the following format: $([name])

The [name] can be any word (containing alfanumeric chars) and is case sensitive.

 Example1: 'The $(Quick) Brown fox jumps over the lazy dog'
 Example2: '$(the) $(Quick) Brown fox jumps over $(the) lazy dog'
 Example3: '$(the) $(Quick) Brown $(fox) jumps over $(the) lazy $(dog)'

What is the best way in javascript to retrieve all place holders so that we have following result:

 Example1: ['Quick']
 Example2: ['the', 'Quick', 'the']
 Example3: ['the', 'Quick', 'fox', 'the', 'dog']

I also need to retrieve a unique list of placeholders, thus:

 Example1: ['Quick']
 Example2: ['the', 'Quick']
 Example3: ['the', 'Quick', 'fox', 'dog']

Thank you.

Have you heard about regular expressions?

freakish
– freakish

2012-06-27 08:44:30 +00:00
Commented Jun 27, 2012 at 8:44 — freakish
– freakish, Commented Jun 27, 2012 at 8:44
The placeholder tag has totally different meaning.

user447356
– user447356

2012-06-27 08:46:07 +00:00
Commented Jun 27, 2012 at 8:46 — user447356
– user447356, Commented Jun 27, 2012 at 8:46
P.S. What have you tried?

freakish
– freakish

2012-06-27 08:55:51 +00:00
Commented Jun 27, 2012 at 8:55 — freakish
– freakish, Commented Jun 27, 2012 at 8:55

Richard · Accepted Answer · 2012-06-27 09:11:48Z

3

As other answers have mentioned, your best approach is to use regular expression ~~with the JavaScript string.match() function~~. My regular expression isn't the best it could be [whose is], but this should do the trick:

jsFiddle Demo

function getPlaceholders(str)
{
    var regex = /\$\((\w+)\)/g;
    var result = [];

    while (match = regex.exec(str))
    {
        result.push(match[1]);    
    }

    return result;
}

Thanks freakish

edited Jun 27, 2012 at 9:11

answered Jun 27, 2012 at 8:57

Richard

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1 Comment

freakish Over a year ago

Few modifications: use regex = /\$$(\w+)$/g and arr = []; while(match=regex.exec(example1)){ arr.push((match[1])); } and we're there.

NimChimpsky · Accepted Answer · 2012-06-27 08:50:22Z

0

Use a regular expression with string's match function

answered Jun 27, 2012 at 8:50

NimChimpsky

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Comments

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

Read this

http://net.tutsplus.com/tutorials/php/advanced-regular-expression-tips-and-techniques/

http://swtch.com/~rsc/regexp/regexp1.html

you can see more on Bookmark

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Jun 27, 2012 at 8:51

xkeshav

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How to get placeholder from string in Javascript?

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http://net.tutsplus.com/tutorials/php/advanced-regular-expression-tips-and-techniques/

http://swtch.com/~rsc/regexp/regexp1.html

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