Matching Values from Multiple Arrays

Question

I only have a basic understanding of coding and hope for your help. I have this js code giving me a true false log for all sausage dog occurrences in the array:

var myAnimal = "Sausage Dog";
var arrayAnimal =["Sausage Dog", "Tiger", "Sausage Dog", "Crocodile", "Lion"];
for (var i = 0; i < arrayAnimal.length; i++) {
  if(myAnimal == arrayAnimal[i]) {
     console.log("True");
     } else {
       console.log("False");
     }
}

How would I do the same task if var myAnimal was an array with multiple strings?

So it would check every animal in myAnimal against every animal in var arrayAnimal and return a true/false for all occurrences.

Is there a way of doing that?

Please don't put tags in question titles

Liam
– Liam

2017-06-15 11:10:18 +00:00
Commented Jun 15, 2017 at 11:10 — Liam
– Liam, Commented Jun 15, 2017 at 11:10

daan.desmedt · Accepted Answer · 2017-06-15 11:12:40Z

2

Something like this: Loop the myAnimal array inside the arrayAnimal loop - checking them for equality.

var myAnimal =  ["Sausage Dog", "Tiger"];
var arrayAnimal = ["Sausage Dog", "Tiger", "Sausage Dog", "Crocodile", "Lion"];
for (var i = 0; i < arrayAnimal.length; i++) {
     for (var j = 0; j < myAnimal.length; j++) {
     		if(arrayAnimal[i] == myAnimal[j]) console.log('match');
     }
}

answered Jun 15, 2017 at 11:12

daan.desmedt

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1 Comment

tip_tip Over a year ago

Thanks a lot, this is really helpful! getting this to a more abstract level - do you also have a solution for this when myAnimal is an array with regular expressions instead of the above mentioned strings?

Ori Drori · Accepted Answer · 2017-06-15 11:15:26Z

1

Create a dictionary from the myAniml array using Array#reduce , and then Array#map the arrayAnimal using the dictionary.

var myAnimal = ["Sausage Dog", "Lion"];
var myAnimalDict = myAnimal.reduce(function(dict, str) {
  dict[str] = true;
  
  return dict;
}, Object.create(null));

var arrayAnimal =["Sausage Dog", "Tiger", "Sausage Dog", "Crocodile", "Lion"];

var result = arrayAnimal.map(function(str) {
  return !!myAnimalDict[str];
});

console.log(result);

answered Jun 15, 2017 at 11:15

Ori Drori

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3 Comments

daan.desmedt Over a year ago

Upvoted your answer since it's also a working approach. It just takes a little less time then the loop approach above.

Ori Drori Over a year ago

It's actually O(n), and much faster than having a loop inside a loop O(n^2)

daan.desmedt Over a year ago

I meant the other way around, my bad. Edited comment.

Heena Khichadiya · Accepted Answer · 2017-06-15 11:24:45Z

0

var myAnimal = ["Sausage Dog", "Tiger", "Sausage", "Crocodile", "Lion"];
var arrayAnimal =["Sausage Dog", "Tiger","Crocodile", "Lion"];
for (var i = 0; i < myAnimal.length; i++) {
    for (var j = 0; j < arrayAnimal.length; j++) {
        if (myAnimal[i] == arrayAnimal[j]) {
          $('#demo').append("True</br>");
        }
    }
}

answered Jun 15, 2017 at 11:24

Heena Khichadiya

1

1 Comment

Tim Hutchison Over a year ago

While code alone may answer the question, it is always best to provide an explanation and any relevant resources as well.

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