Javascript Function to split and return a value from a string

Question

I am trying to grab a certain value. I am new to javascript and I can't figure out why this is not working.

If I parse "kid_2" I should get "kostas". Instead of "Kostas" I always get "02-23-2000". So I must have a logic problem in the loop but I am really stuck.

function getold_val(fieldname,str){

  var chunks=str.split("||");
  var allchunks = chunks.length-1;
     for(k=0;k<allchunks;k++){
       var n=str.indexOf(fieldname);
       alert(chunks[k]);
       if(n>0){
       var chunkd=chunks[k].split("::");
         alert(chunkd);
         return chunkd[1];
       }
     }
}
var test = getold_val('kid_2','date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||');

alert(test);

It should be allchunks = chunks.length not allchunks = chunks.length-1 — slebetman
– slebetman, Commented Sep 26, 2012 at 17:10
Also, it should be if(n>=0) because if the key is found it really is at position 0. — slebetman
– slebetman, Commented Sep 26, 2012 at 17:13
I have tried all of these.. check this it may help you. jsbin.com/efajug/3/edit. Problem is that it is stucked in the first split, so the loop is not working right. — George D.
– George D., Commented Sep 26, 2012 at 17:17

canon · Accepted Answer · 2012-09-27 03:51:15Z

2

A regex may be a little more appealing. Here's a fiddle:

function getValue(source, key){
    return (new RegExp("(^|\\|)" + key + "::([^$\\|]+)", "i").exec(source) || {})[2];
}    
getValue("date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||","kid_2");

But if you want something a little more involved, you can parse that string into a dictionary like so (fiddle):

function splitToDictionary(val, fieldDelimiter, valueDelimiter){
    var dict = {},
    fields = val.split(fieldDelimiter),
    kvp;
    for (var i = 0; i < fields.length; i++) {        
        if (fields[i] !== "") {
            kvp = fields[i].split(valueDelimiter);        
            dict[kvp[0]] = kvp[1];
        }
    }
    return dict;    
}
var dict = splitToDictionary("date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||","||","::");
console.log(dict["date_1"]);
console.log(dict["date_2"]);
console.log(dict["kid_1"]);
console.log(dict["kid_2"]);

edited Sep 27, 2012 at 3:51

answered Sep 26, 2012 at 17:52

canon

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1 Comment

George D. Over a year ago

I am a newbie in Jscript so regular expressions - as you can imagine - was too advanced. I really thank you both suggestions work perfect.

Mihai Stancu · Accepted Answer · 2012-09-26 17:18:55Z

2

This works, here's my fiddle.

function getold_val(fieldname,str) {
    var chunks = str.split('||');
    for(var i = 0; i < chunks.length-1; i++) {
        if(chunks[i].indexOf(fieldname) >= 0) {
            return(chunks[i].substring(fieldname.length+2));
        }
    }
}
alert(getold_val('kid_2', 'date_1::02-23-2000||date_2::06-06-1990||kid_1::George||kid_2::Kostas||'));

The issue with your code was (as @slebetman noticed as well) the fact that a string index can be 0 because it starts exactly in the first letter.

The code is almost the same as yours, I just didn't use the second .split('::') because I felt a .substring(...) would be easier.

edited Sep 26, 2012 at 17:18

answered Sep 26, 2012 at 17:08

Mihai Stancu

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7 Comments

George D. Over a year ago

my god you're very fast. Let me check it one moment please.

Barmar Over a year ago

Actually, the main problem was that he was doing str.indexOf() instead of chunks[i].indexOf(). So while looking at the first chunk, it would find the fieldname in a different chunk.

slebetman Over a year ago

Actually, using indexOf is also a bug. Should simply split everything into an array of arrays (or array of objects) and simply check if key = fieldname. This will break on kid_10 and above.

George D. Over a year ago

your code works great but I had to add "+2" to get ride of the dots. return(chunks[i].substring(fieldname.length+2)); I'll keep searching how to do it with the "::" as a seperator. @Barman I think you saw exactly the problem. I'll test it in a minute.

Barmar Over a year ago

I figured it out by adding lots of console.log statements. When I logged n it said it was something like 65!

|

Vivin Paliath · Accepted Answer · 2012-09-26 17:34:54Z

2

There are two bugs. The first error is in the indexOf call:

var n = str.indexOf(fieldname);

This will always return a value greater than or equal to 0 since the field exists in the string. What you should be doing is:

var n = chunks[k].indexOf(fieldname);

The second error is in your if statement. It should be:

if(n >= 0) {
   ...
}

or

if(n > -1) {
    ...
}

The substring you are looking for could very well be the at the beginning of the string, in which case its index is 0. indexOf returns -1 if it cannot find what you're looking for.

That being said, here's a better way to do what you're trying to do:

function getold_val(fieldName, str) {
    var keyValuePairs = str.split("||");
    var returnValue = null;

    if(/||$/.match(str)) {
       keyValuePairs = keyValuePairs.slice(0, keyValuePairs.length - 1);
    }

    var found = false;
    var i = 0;
    while(i < keyValuePairs.length && !found) {
       var keyValuePair = keyValuePairs[i].split("::");

       var key = keyValuePair[0];
       var value = keyValuePair[1];

       if(fieldName === key) {
          returnValue = value;
          found = true;
       }

       i++;
    }

    return returnValue;
}

edited Sep 26, 2012 at 17:34

answered Sep 26, 2012 at 17:07

Vivin Paliath

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8 Comments

Vivin Paliath Over a year ago

Mihai, good point - my mistake; I didn't see the || at the end.

slebetman Over a year ago

@VivinPaliath That return looks correct though. It is only executed if the key matches.

slebetman Over a year ago

I really think the real bug is the if statement.

slebetman Over a year ago

Don't use indexOf. Do chunks[k].split('::')[0] = fieldname. Think what will happen with kid_10

slebetman Over a year ago

No, think about if kid_10 exists and kid_1 is passed in.

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