CODEWITHSUNDEEP
javascriptarraysunderscore.js
Sylar
Sylar

Reputation: 12072

Opposite of underscore ._without(array, value)

Looking at the underscore array methods, I dont see what I want to accomplish.

This removes 0 and 1 from the array:

_.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
=> [2, 3, 4]

What if I need only 0 and 1?

=> [1, 1, 0 ,1]

Underscorde would make me write less javascript code.

Clarity:

Example if 0, 1 is in the array, leave all values of 1's and 0's.

Upvotes: 3

Views: 764

Answers (3)

kriskot
kriskot

Reputation: 303

The simplest underscore way I found is this:

var arr = [1, 2, 1, 0, 3, 1, 4];
console.log(_.difference(arr, _.without(arr, 1, 0)));

or if you have your args in an array:

console.log(_.difference(arr, _.difference(arr, [1, 0])));

Upvotes: 0

Are
Are

Reputation: 2241

Here is what I found:

var allArray = [1, 2, 1, 0, 3, 1, 4];
var leaveOnly = [1, 0];

var result = _.filter(allArray, _.partial(_.contains, leaveOnly)); // [1, 1, 0, 1]

_.filter, _.contains, _.partial

JSFiddle: https://jsfiddle.net/eeLcrmvt/

If you are going to use this quite often, you can create a mixin:

_.mixin({
  filterOut: function(arr, leave) {
    return _.filter(arr, _.partial(_.contains, leave))
  }
});

var result = _.filterOut([ 1, 2, 0, 1, 4, 3, 1 ], [ 0, 1 ]);

console.log(result); // [ 1, 0, 1, 1 ]

Upvotes: 3

steo
steo

Reputation: 4656

The underscore way

var zerosones = _.filter([1, 2, 1, 0, 3, 1, 4], function(num){ 
    return (num === 0 || num === 1); 
});
=> [1, 1, 0, 1]

using _.filter method

Without underscore ( es5 ) you can use Array#filter with a pretty good compatibility 

var completeArray = [1, 2, 1, 0, 3, 1, 4];
completeArray =  completeArray.filter(function(value){ 
   return (value === 1 || value === 0) 
});

console.log(completeArray); //[1, 1, 0, 1]

Upvotes: 0

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