Replace underscore with brackets using javascript

Question

I have a string AverageLogon_Seconds_

I need to replace the first underscore with '(' and second Underscore with ')'.

Means I need to get the text like AverageLogon(Seconds).

I have checked with str.replace(/_/g, ')'); , but it will replace both the underscore iwth ')'.

Can anyone help me on this.

Thanks

A loop based method would be to use a loop and work on the string but not efficient maybe. — Gandalf the White
– Gandalf the White, Commented Aug 2, 2016 at 6:59
Remove the global flag g and repeat. str.replace(/_/, '(').replace(/_/,')') — tewathia
– tewathia, Commented Aug 2, 2016 at 6:59
Will you be getting only two brackets in all your string occurences? — David R
– David R, Commented Aug 2, 2016 at 7:00
@DavidR Not sure I need t replace the _ with brackets simultaneously — S M
– S M, Commented Aug 2, 2016 at 7:00
@tewathia, please add that as an answer.. so that I can mark it as accepted. It works perfectly for me. — S M
– S M, Commented Aug 2, 2016 at 7:10

Pranav C Balan · Accepted Answer · 2016-08-02 07:12:00Z

4

Do it with String#replace with a callback and a counter variable. Replace _ with ( in an odd position and ) in an even position where the counter variable can be used for finding out the position.

var str = 'AverageLogon_Seconds_',
  i = 0;

var res = str.replace(/_/g, function() {
  return i++ % 2 == 0 ? '(' : ')';
});

console.log(res);

edited Aug 2, 2016 at 7:12

answered Aug 2, 2016 at 7:00

Pranav C Balan

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2 Comments

S M Over a year ago

Thanks pranav... But I think str.replace(/_/, '(').replace(/_/,')') this one is more perfect

Pranav C Balan Over a year ago

@Manu : it will only work if there if there is only 2 _ in string .... if more than 2 are there which only replace the first two.... otherwise which is perfect and simple :)

Phil · Accepted Answer · 2016-08-02 07:14:47Z

3

I feel like it would be more prudent to target the "_something_" pattern as a whole. Something like

str.replace(/_([a-z0-9 -]+)_/gi, '($1)')

You can narrow that [a-z0-9 -] character class down based on the characters you expect to appear between the underscores. For now, I've got letters, numbers, spaces and hyphens.

var tests = [
  'AverageLogon_Seconds_',
  'AverageLogon_Seconds_ and some other_data_',
  'Oh no, too_many_underscores___'],
    out = document.getElementById('out'),
    rx = /_([a-z0-9 -]+)_/gi;

tests.forEach(function(test) {
  out.innerHTML += test + ' => ' + test.replace(rx, '($1)') + '\n';
});

<pre id="out"></pre>

edited Aug 2, 2016 at 7:14

answered Aug 2, 2016 at 7:05

Phil

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Comments

Sameer Srivastava · Accepted Answer · 2016-08-02 07:04:26Z

1

Thats easy. Just a one liner needed.

testString = "AverageLogon_Seconds_";

replacedString = testString.replace(/_/, '(').replace(/_/, ')');

console.log(replacedString);

Output : "AverageLogon(Seconds)"

answered Aug 2, 2016 at 7:04

Sameer Srivastava

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1 Comment

IInspectable Over a year ago

Keep in mind, that this only works for input with no more then two underscores. This answers the immediate question, but is not generally applicable.

tsadkan yitbarek · Accepted Answer · 2016-08-02 07:13:53Z

1

var str = 'AverageLogon_Seconds_', replacement = ')';

//replace the last occurence  of '_' with ')'
str = str.replace(/_([^_]*)$/,replacement+'$1');

//replace the remaining '_' with '('
console.log(str);

edited Aug 2, 2016 at 7:13

answered Aug 2, 2016 at 7:01

tsadkan yitbarek

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Comments

Vinay · Accepted Answer · 2016-08-02 07:15:07Z

1

Pranav's solution is nice. I tend to like to write things that I can very quickly reason about (i.e. sometimes less elegant). Another way (read in DJ Khaled's voice):

function replaceUnderscores(str) {
  return str.split('_').map(function (part, ind) {
    if (part === '') {
      return '';
    }
    if (ind % 2 === 0) {
      return part + '(';
    } else {
      return part + ')';
    }
  }).join('');
}

// "AverageLogon(Seconds)"
console.log(replaceUnderscores('AverageLogon_Seconds_'));

edited Aug 2, 2016 at 7:15

answered Aug 2, 2016 at 7:13

Vinay

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1 Comment

Vinay Over a year ago

They don't want you to answer questions on SO

Ekansh Rastogi · Accepted Answer · 2016-08-02 07:02:12Z

-2

will this work

var t = "AverageLogon_Seconds_";
var ctr=0;
while(t.contains('_')){
  if(ctr==0){
    t= t.replace('_','(');
    ctr++;
  }
  else{
    t= t.replace('_',')');
    ctr--;
  }
}

answered Aug 2, 2016 at 7:02

Ekansh Rastogi

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