CODEWITHSUNDEEP
javascriptjqueryarraysstring
user3741635
user3741635

Reputation: 862

How to rearrange JavaScript array using match?

Let say that we have the JavaScript array arr, where each arr[i] contains a sentence. Now If we want to search for the sentences that contain a particular string str, we can use match to find these sentence using 

var newarr = [];                
for(var i = 0; i < arr.length; i++) {
if(arr[i].toLowerCase().match(str.toLowerCase()){       
newarr[newarr.length] = arr[i];             
}
}

The new array newarr will contain only the sentence that contain the string str. Now, is there a way to rearrange newarr so that the sentences containing str in beginning be first, then the ones that containing str in the middle then the ones containing strin the end?

Upvotes: 2

Views: 90

Answers (2)

Chris Hunt
Chris Hunt

Reputation: 4030

The sort method available on Arrays can take a custom function that compares elements and sorts according to that. Your custom sort function needs to take two arguments, a and b, and return a number; a and b are elements of your array which are being compared. The number that your function returns tells the sort function whether a or b should come first, according to the following rules:

  • if the returned number is <0, then a comes before b
  • if the returned number is >0, then b comes before a
  • if the returned number is 0, then a and b are "the same" order-wise

So to order an array of strings according to where a substring str appears, then you can do something like this:

var arr = ['bbbab', 'bbabbb', 'abbb', 'bbbba'];

// Our substring.
var str = 'a';
// Make copy of array.
var newarr = arr.slice()
// Sort.
newarr.sort(function (a, b) {
  return a.indexOf(str) - b.indexOf(str);
});
console.log(newarr); // => ["abbb", "bbabbb", "bbbab", "bbbba"]

Upvotes: 2

5eeker
5eeker

Reputation: 1027

You have forgotten one parenthesis in your if condition.

http://jsfiddle.net/pandeyaditya/LbwgfLvt/

Check below code : 

var arr = ["JS is fun", "JS Rocks", "JS is for techies"];
var newarr = [];
var str = "fun";
for(var i = 0; i < arr.length; i++) {
if(arr[i].toLowerCase().match(str.toLowerCase())){       
newarr[newarr.length] = arr[i];             
}
}
   alert(newarr);

Upvotes: -1

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