How to split string with subtotal prefix

Question

I want to split string

'something.somethingMore.evenMore[123].last'

to

['something',
'something.somethingMore',
'something.somethingMore.evenMore[123]',
'something.somethingMore.evenMore[123].last']

I can't figure out simple solution to split string by separator '.', but with preceding content of string.

score 3 · Accepted Answer · 2014-09-11T13:33:59.363

Modern JS programming style would be something like

str                                             //take the input
    .split('.')                                 //and split it into array of segments,
    .map(                                       //which we map into a new array,
        function(segment, index, segments)      //where for each segment
            return segments.slice(0, index+1)   //we take the segments up to its index
                .join(".")                      //and put them back together with '.'
            ;
         }
    )

This takes advantage of the fact that the Array#map function passes not only the current value, but also its index and the entire input array. That allows us to easily use slice to get an array containing all the segments up to the current one.

Nice solution. Thanks. I tried matching with regex but no luck to do it universal. — Peter Dub, Sep 12 '14 at 07:51

score 2 · Answer 2 · answered Sep 11 '14 at 13:19

I wouldn't call my solution simple but:

function splitArrayIntoGoofyArray(val){
  var str =val.split("."), arr = [];
  for (var x = str.length; x >= 1; x--){
     var cnt = str.length - x;
     arr.push((cnt > 0) ? arr[cnt - 1] + "." + str[cnt] : str[cnt]);
  }
  return arr;
}
console.log(splitArrayIntoGoofyArray("aaa.bbb.ccc.ddd"));

http://jsfiddle.net/7tav4sue/

Avinash Raj · Answer 3 · 2014-09-11T13:25:26.863

2

You could try matching instead of splitting,

> var s = 'something.somethingMore.evenMore[123].last';
undefined
> var regex = /(?=(^((([^.]*)\.[^.]*)\.[^.]*)\.[^.]*))/g;
undefined
> regex.exec(s)
[ '',
  'something.somethingMore.evenMore[123].last',
  'something.somethingMore.evenMore[123]',
  'something.somethingMore',
  'something',
  index: 0,
  input: 'something.somethingMore.evenMore[123].last' ]

To get the desired output,

> regex.exec(s).slice(1,5)
[ 'something.somethingMore.evenMore[123].last',
  'something.somethingMore.evenMore[123]',
  'something.somethingMore',
  'something' ]

edited Sep 11 '14 at 13:25

answered Sep 11 '14 at 13:19

Avinash Raj

172,303
28
230
274

Very clever, although I'm not quite sure how it works. – Sep 11 '14 at 13:35
You dont need regex here. You could split and loop – user3077033 Sep 11 '14 at 13:37

score 2 · Answer 4 · answered Sep 11 '14 at 13:22

It depends on what is simple solution. The easiest way to do it is to create first array with

var str = 'something.somethingMore.evenMore[123].last';
var arr = str.split('.');

And then fill new array with this data

var result = [];
for (var i = 0; i < arr.length; i++) {
    var item = [];
    for (var j = 0; j <= i; j++) {
        item.push(arr[j]);
    }
    result.push(item.join('.'))
}

score 1 · Answer 5 · answered Sep 11 '14 at 13:03

1

I guess you'll need a loop :

while finding "." character, return in a list substring till new "." index. Use the last correct index found to start each search.

answered Sep 11 '14 at 13:03

Hellin

62
8

How to split string with subtotal prefix

5 Answers5