CODEWITHSUNDEEP
javascriptstring-matchingindexof
maudulus
maudulus

Reputation: 11045

Use javascript to return true if a string contains an exact match

I've been using the .indexOf('') > -1 in order to check whether there's a match in a string. The problem that I'm having is that when I'm performing the match on multiple strings, I get a match on the string for both EIFT and EI (since EIFT contains EI), and so the function returns true for both sentences. What I need is a way for this to only return true for function eIft if the string is "EIFT", but not for EI.

My current code is as follows, and I've been trying to think of ways around this but haven't had any success yet. 

function eI(mystring){
    return mystring.indexOf("EI") > -1
}

function eIft(mystring){
    return mystring.indexOf("EIFT") > -1
}

Thanks!

Upvotes: 3

Views: 6930

Answers (2)

Bic
Bic

Reputation: 3134

If you are checking inside a string for you values (e.g. heleilo), then you need to confirm your positive results for the 'EI' check:

function eI(mystrng) {
    return mystring.indexOf("EI") != -1 && !eIFt(mystring);
}

This would only work provided they don't both exist in different occurences (e.g. heleileifto). In this case, you have to check the immediate following characters:

function eI(mystring) {
    var pos = mystring.indexOf("EI");

    if (pos != -1) { // found
        var char1 = mystring[pos + 2];
        var char2 = mystring[pos + 3];

        return char1 !== 'F' && char2 !== 'T';
    }
}

OR

function eI(mystring) {
    var pos = mystring.indexOf("EI");

    if (pos != -1) { // found
        return pos != eIFt(mystring); // they won't have the same index
    }
}

Upvotes: 1

Jacob
Jacob

Reputation: 78920

You can use ===; that will do an exact match of strings. Use indexOf only if you're checking whether the string contains another string.

function eI (mystring) {
    return mystring === "EI";
}

function eIFt(mystring) {
    return mystring === "EIFT";
}

Upvotes: 2

Related Questions