CODEWITHSUNDEEP
javascriptstringsplit
Netorica
Netorica

Reputation: 19337

to UpperCase certain char-index in a string Javascript

ok I want do have a jscript below

$(document).ready(function(){
    var str = 'post'; //the subject string
    var arr =[0,2]; //to uppercase character index 0 and 2

    str = str.split("");
    for(var i = 0; i < str.length; i++){
        if($.inArray(i,arr)){
            str[i] = str[i].toUpperCase();
        }
    }
    str = str.join('');
    alert(str);
    //the result must be PoSt
});

and you may see it running here

http://jsfiddle.net/laupkram/WfUUp/ ​

now what I want there is to provide a subject string and an array.

the subject string is the string to be process and the array contains numerical values that will represent the character index in the string to uppercase.

did i miss something with my script that's why I get undersirable results?

Upvotes: 3

Views: 6300

Answers (4)

Nick
Nick

Reputation: 1869

I would re-write this as 

var str = 'post'; //the subject string
var arr =[0,2]; //to uppercase character index 0 and 2

str = str.split("");
for(i = 0; i < arr.length; i++){
  str[arr[i]]=str[arr[i]].toUpperCase();

}
str = str.join('');
alert(str);

http://jsfiddle.net/NBBgz/

Upvotes: 1

mtk
mtk

Reputation: 13709

2 Things that I see wrong here:

  1. No need to split the str, you can loop over it normally.

  2. You got inArray() wrongly. The below snippet from jquery api for inArray

The $.inArray() method is similar to JavaScript's native .indexOf() method in that it returns -1 when > it doesn't find a match. If the first element within the array matches value, $.inArray() returns 0.

So, as inArray is returning -1 for indexes that it didn't find, you if statement is becoming true, and hence you are getting the result as 'PoST'.

Upvotes: 1

gideon
gideon

Reputation: 19465

Check the docs for $.inArray . It returns the index of the element that was found or -1 if not found.

$(document).ready(function(){
    var str = 'post'; //the subject string
    var arr =[0,2]; //to uppercase character index 0 and 2

    str = str.split("");
    for(var i = 0; i < str.length; i++){
        //CHANGE HERE
        if($.inArray(i,arr) != -1){
                          //^^ change this
            str[i] = str[i].toUpperCase();
        }
    }
    str = str.join('');
    alert(str);
    //the result must be PoSt
});

​

Upvotes: 3

Diode
Diode

Reputation: 25145

$(document).ready(function() {
    var str = 'post'; //the subject string
    var arr = [0, 2]; //to uppercase character index 0 and 2
    str = str.split("");
    for (var i = 0; i < arr.length; i++) {
        if (str[arr[i]]) {
            str[arr[i]] = str[arr[i]].toUpperCase();
        }
    }
    str = str.join('');
    alert(str);
    //the result must be PoSt
});

Upvotes: 3

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