Check Whether an Array Is a Subset of Another

Check whether an array is a subset of another

bool isSubset = !t2.Except(t1).Any();

Find whether an array is subset of another array hashtable way(Python)

In Python, you would use set objects for this:

>>> arr1 =  [11, 1, 13, 21, 3, 7]
>>> arr2 = [11, 3, 7, 1]
>>> set(arr1).issuperset(arr2)
True

Or more efficiently, use:

>>> set(arr2).issubset(arr1)
True

If you expect arr2 to be much smaller...

Some quick timings, it seems that they are about the same in rumtime, although, creating a set from arr1 will require much more auxiliary memory:

>>> import numpy as np
>>> arr1 = np.random.randint(0, 100, (1000000,)).tolist()
>>> len(arr1)
1000000
>>> from timeit import timeit
>>> arr2 = [11, 3, 7, 1]
>>> timeit('set(arr1).issuperset(arr2)', 'from __main__ import arr1, arr2', number=1000)
14.337173405918293
>>> timeit('set(arr2).issubset(arr1)', 'from __main__ import arr1, arr2', number=1000)
14.459818648989312

Checking if an array is a subset of another array (but checking against a property)

var object1 = {name: 'one'};
var object2 = {name: 'two'};
var object3 = {name: 'three'};

var arr1 = [object1,object2,object3];
var arr2 = ['one','two'];

// solution
var names = arr1.map(function(obj) { 
  return obj.name; 
});

var isSuperset = arr2.every(function(val) { 
  return names.indexOf(val) >= 0;
});

alert(isSuperset);

Test if one array is a subset of another

If you start from strings, you could check strstr($fullString,$subsetStr);. But that'll only work when all chars have the same order: 'abcd','cd' will work, but 'abcd','ad' won't.

But instead of writing your own, custom, function you should know that PHP has TONS of array functions, so its neigh on impossible that there isn't a std function that can do what you need it to do. In this case, I'd suggest array_diff:

$srcString = explode('>','string1>string2>string3>string4>string5');
$subset = explode('>','string3>string2>string5');
$isSubset = array_diff($subset,$srcString);
//if (empty($isSubset)) --> cf comments: somewhat safer branch:
if (!$isSubset)
{
    echo 'Subset';
    return true;
}
else
{
    echo 'Nope, substrings: '.implode(', ',$isSubset).' Didn\'t match';
    return false;
}

JEST - check if objects array is a subset of another array

I've never tried this myself, but wouldn't it work to just say:

expect(users).toEqual(
  expect.arrayContaining(subset)
)

Check if an array is subset of another array in Ruby

Use sets. Then you can use set.subset?. Example:

require 'set'

a1 = Set[3,6,4]
a2 = Set[1,2,3,4,5,6,7,8,9]

puts a1.subset?(a2)

Output:

true

See it working online: ideone

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