Iterate a string with Regex and JS

Question

I have a set of structured data into a string and I need to iterate over it through regular espression in Javascript.

This is an example of the data:

|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4

I need to parse them and create a structured object (or an array) like this:

myObject.KEY1 = "VALUE 1"
myObject.KEY2 = "VALUE 2"
myObject.KEY3 = "OTHER VALUE WITH ANY CHARACTER LIKE SPACES, AND WHAT YOU WANT"
myObject.KEY4 = "VALUE4"

I've got the keys with that simple regex:[|](.+?)[|] but I don't know how to iterate through them and thei respective values.

If you are allowed to have your delimiter | in your data then you must have some way to escape it. There is absolutely no way to distinguish that |PIPES| is not a new key, followed by a new value. Even if keys have a very rigid format, I can always put something that looks like a key in the data. e.g. |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, \|PIPES\| AND WHAT YOU WANT — Stephen P
– Stephen P, Commented Jan 20, 2015 at 21:33
You are right. I've looked through the data and there isn't that occourrence. So forgot the meta-pipe problem ;) — Pennywise83
– Pennywise83, Commented Jan 20, 2015 at 21:41
@Pennywise83 What kind of source is delivering data in this format? — Mouser
– Mouser, Commented Jan 20, 2015 at 21:47
Why regex? This seems like a simple string manipulation problem. — Mike Brant
– Mike Brant, Commented Jan 20, 2015 at 21:56

Ixrec · Accepted Answer · 2015-01-20 21:41:11Z

2

I'm going to assume that a key is defined by the expression \|KEY[0-9]+\|, since that's the simplest way to include |KEY1| through |KEY4| while also excluding |PIPES|.

If your goal is to use a loop and regex matches, as opposed to a single convoluted regex or doing actual parsing with functions like indexOf(), then this can be done with negative lookahead.

var x = "|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4";

var map = {};

while(x.length > 0) {
    var key = x.match(/\|KEY[0-9]+\|/)[0];
    x = x.substr(key.length);
    var value = x.match(/(.(?!\|KEY[0-9]+\|))*/)[0];
    x = x.substr(value.length);
    map[key] = value;
}

alert(JSON.stringify(map, null, 4));

http://jsfiddle.net/eyL7yhwr/

answered Jan 20, 2015 at 21:41

Ixrec

9761 gold badge7 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Mouser · Accepted Answer · 2015-01-20 21:54:31Z

2

This will do it.

//using regex
var keyString = "|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4"
var cases = keyString.match(/[^|]+/g)
var myObject = {};
if (cases.length > 0)
  {
     for (var i = 0; i < cases.length; i += 2)
     {
       myObject[cases[i].toString()] = cases[i+1].trim();
     }
  }
  
  document.write(JSON.stringify(myObject));

edited Jan 20, 2015 at 21:54

answered Jan 20, 2015 at 21:41

Mouser

13.3k3 gold badges31 silver badges54 bronze badges

3 Comments

Ixrec Over a year ago

The sample output in the question shows that "|PIPES|" is not supposed to be one of the keys, so this answer is incorrect (unless he changes his mind about that requirement).

Mouser Over a year ago

@Ixrec "You are right. I've looked through the data and there isn't that occourrence. So forgot the meta-pipe problem ;)" as commented by the OP.

Ixrec Over a year ago

In retrospect it's hard to tell whether he actually wanted "|PIPES|" to be a key or not, so I'll just +1 and we'll call it a draw.

Rodion · Accepted Answer · 2015-01-20 22:41:26Z

0

You can do something like this:

var s = "|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4";

s.match(/\|(KEY\d+)\|.*?(?=\|KEY\d|$)/g).reduce(function (res, v) { 
  var match = v.match(/(KEY\d+)\|(.*?)\s*$/);
  res[match[1]] = match[2];
  return res;
}, {})

another solution even easier:

var s = "|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4";

var v, res = {}, match = s.match(/\s*\|KEY\d+\|\s*|.+?(?=\s*\|KEY\d|$)/g);
while(v = match.shift()) 
  res[v.replace(/^[\s|]*|[\s|]*$/g, '')] = match.shift();

edited Jan 20, 2015 at 22:41

answered Jan 20, 2015 at 21:43

Rodion

5312 silver badges10 bronze badges

Comments

1252748 · Accepted Answer · 2015-01-20 23:49:48Z

0

Something like exec and /[^|]+/g will get you a nice array.

var str = "|KEY1|VALUE 1 |KEY2| VALUE 2 |KEY3| OTHER VALUE WITH ANY CHARACTER LIKE SPACES, |PIPES| AND WHAT YOU WANT |KEY4| VALUE4";

var re = /[^|]+/g;

var arr = [];

while ((arr = re.exec(str)) !== null){
  console.log(arr[0].trim());
}

fiddle

It's a bit simpler than some other regex here, and I think it's a bit more readable. I also used trim(), which you'll have to use the polyfill if you want to support before IE9.

edited Jan 20, 2015 at 23:49

answered Jan 20, 2015 at 21:50

1252748

15.5k35 gold badges118 silver badges244 bronze badges

Collectives™ on Stack Overflow

Iterate a string with Regex and JS

4 Answers 4

Comments

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related