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

Answer 1

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); 

Answer 2

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> 

Answer 3

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

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

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

Answer 4

Thats easy. Just a one liner needed.

testString = "AverageLogon_Seconds_";

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

console.log(replacedString);

Output : "AverageLogon(Seconds)"

Answer 5

Pranav's solution is nice. I tend to like to write things that I can very quickly reason about (ie 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_')); 

Answer 6

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--;
  }
}