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.

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.

• javascript
• regex
• regex-group
• subtotal

Share Improve this question Follow edited Dec 17, 2017 at 15:06 ekad 14.6k2626 gold badges4646 silver badges4848 bronze badges asked Sep 11, 2014 at 12:57 Peter DubPeter Dub 53111 gold badge66 silver badges1414 bronze badges

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5 Answers 5

Sorted by: Reset to default 3

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.

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.bbbc.ddd"));

http://jsfiddle/7tav4sue/

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('.'))
}

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' ]

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.