Extracting multiple strings

Question

I am trying to extract multiple parameter strings from the following kind of input:

var paramsString = "first='somevalue' second='another value' third='another'"

With the resulting object:

var paramsObject = { 
    first: 'somevalue', 
    second: 'another value', 
    third: 'another' 
};

I initially thought I could do paramsString.split(" ") but then I realised (as illustrated above) that some of the values could have spaces in.

I then thought maybe a RegEx like:

paramsObject.first = paramsString.match("first='(.*)'")[0];

But that goes all the way to the last ' character after the third value.

I could do this with indexOf() and substring but that seems really verbose espsecially when scaling to more parameters.

What is the most efficent and neat way of doing this?

dfsq · Accepted Answer · 2014-05-29 09:03:42Z

2

You can try this approach:

var paramString = "first='somevalue' second='another value' third='another'"
paramString.match(/\w+='.*?'/g).reduce(function(prev, curr) {
    var parts = curr.split('=');
    prev[parts[0]] = parts[1].replace(/(^'|'$)/g, '');
    return prev;
}, {});

After matching with /\w+='.*?'/g regexp, power of reduce does the rest converting array of matches to the object.

answered May 29, 2014 at 9:03

dfsq

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Pudge601 · Accepted Answer · 2014-05-29 09:03:56Z

1

You can use a while loop and a regex to keep retrieving the key/values from the string and remove that part of the string each time until the regex no longer matches. Something like this should do what you're after;

var paramsString = "first='somevalue' second='another value' third='another'",
    paramsObject = {};

while ((matches = /^ ?([^=]+)='([^']+)' ?/.exec(paramsString))) {
    paramsString = paramsString.substr(matches[0].length);
    paramsObject[matches[1]] = matches[2];
}

answered May 29, 2014 at 9:03

Pudge601

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Neil · Accepted Answer · 2014-05-29 09:08:29Z

1

You're almost there. You should, however, remember that you don't want to capture anything (.*) but rather anything that doesn't indicate the end of the value or '.

So something like /\w+='([^']*)'/g should meet your requirements (I'm assuming the key name will not involve anything complicated). See here for a working example. Hope that helps!

edited May 29, 2014 at 9:08

answered May 29, 2014 at 9:01

Neil

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jslayer · Accepted Answer · 2014-05-29 09:12:19Z

0

function parse(str) {
    var out = {};

    str.match(/([^= ]+='[^']+')/g).forEach(function(sub){
            var m = sub.match(/([^=]+)='([^']+)/i);

            if (m.length === 3) {
                out[m[1]] = m[2];
            }
        }
    );

    return out;
}


parse("a_1='someValue' a_2='another value' a_3='another'");

Than you will have:

{
    a_1 : "someValue",
    a_2 : "another value",
    a_3 : "another"
}

answered May 29, 2014 at 9:12

jslayer

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Alberto De Caro · Accepted Answer · 2014-05-29 16:47:52Z

0

Just another way, using exec instead of match. The main advantage is that the object returned by exec already contains the mathed groups, without any further processing:

var paramsObject = {};
var paramsString = "first='somevalue' second='another value' third='another'";
var re = /(\w+)='([\w ]+)'/gi;

while((ma = re.exec(paramsString)) != null){
    paramsObject [ma[1]] = ma[2];
}

See RegExp.exec references at MDN for further details.

answered May 29, 2014 at 16:47

Alberto De Caro

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