CODEWITHSUNDEEP
javascriptregex
jcera
jcera

Reputation: 345

Getting a substring from a string using regex

I am trying to search for a substring on a given string. 

// format is <stringIndex>~<value>|<stringIndex>~<value>|<stringIndex>~<value>
var test = "1~abc1|2~def2|1~ghi3|4~jk-l4|5~123|6~sj2j";

function getValue(test, stringIndex) {
    // format is <stringIndex>~<value>|<stringIndex>~<value>|<stringIndex>~<value>
    //help with this.
    //I can only get the value if 1 is the passed parameter, here is the code:
    return test.replace(new Regexp(stringIndex + '\~(.+?(?=\|)).+'), '$1');
}

// usage:

getValue(test, '1'); //returns 'abc1', even though there are two 1's
getValue(test, '4'); //returns 'jk-14'
getValue(test, '6'); //returns 'sj2j'
getValue(test, '123213'); // returns ''

Basically, I'm writing a function which accepts the test string and stringIndex as a parameter, and searches the test string using that stringIndex and return the value associated with it. the format of the test string is stated above in the comments. I'm only looking for regex solution without using loops or split.

Upvotes: 0

Views: 72

Answers (3)

user3728205
user3728205

Reputation: 66

Here is an update for the above two answers, we need to add "\b" for the regexp.

// modified the test string.
var test = "311~abc1|2~def2|1~ghi3|4~jk-l4|5~123|6~sj2j";
function getValue(test, stringIndex) {
    var m = test.match(new RegExp("\\b" + stringIndex + "~([^|]+)", 'i')) || [null, null];
    return m[1];
}

> getValue(test, '1');
'ghi3'
> getValue(test, '2');
'def2'
> getValue(test, '11');
null
> getValue(test, '311');
'abc1'

Upvotes: 1

Leo
Leo

Reputation: 13828

There are plenty ways of writing regular expression for matching a pattern, it really depends on the specificity of your use case. Here is one solution:

var test = "1~abc1|2~def2|1~ghi3|4~jk-l4|5~123|6~sj2j";
function getValue(test, stringIndex) {
    var matches = test.match(new RegExp(stringIndex + "~([\\w-]+)\\|?"));
    return matches ? matches[1] : "";
}

getValue(test, '1'); // 'abc1'
getValue(test, '4'); // 'jk-14'
getValue(test, '6'); // 'sj2j'
getValue(test, '123213'); // ''

Upvotes: 0

anubhava
anubhava

Reputation: 784898

You probably want this regex code:

function getValue(test, stringIndex) {
    // format is <stringIndex>~<value>|<stringIndex>~<value>|<stringIndex>~<value>
    //help with this.
    //I can only get the value if 1 is the passed parameter, here is the code:
    var m = test.match(new RegExp(stringIndex + "~([^|]+)", 'i')) || [null, null];
    return m[1];
}

Then calling it as:

getValue(test, '1');
"abc1"
getValue(test, '4');
"jk-l4"
getValue(test, '6');
"sj2j"
getValue(test, '123213');
null

Upvotes: 1

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