Ruby rails include? array [closed] - ruby-on-rails

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Is it possible to check inclusion array inside array?
i want to check if
primary = [1,2,3] includes secondary = [2,3]
i have tried primary.include?(secondary) => false
need to return bool value

Answer 1

Solution
Without duplicates
If there aren't any duplicate, you can calculate the Array difference, and check if it is empty :
(secondary-primary).empty?
#=> true
General case
subset_of? checks that for every unique element in secondary, there are at least as many elements in primary :
class Array
def count_by
each_with_object(Hash.new(0)) { |e, h| h[e] += 1 }
end
def subset_of?(superset)
superset_counts = superset.count_by
count_by.all? { |k, count| superset_counts[k] >= count }
end
end
Example :
secondary.subset_of?(primary)
#=> true
[2,2].subset_of?([1, 2, 3])
#=> false
This should work for any Array, and it should be faster than other answers for big arrays.
Test
([1,2,3] - [3,4,5,2,1]).empty?
#=> true
([1,2,3,'a'] - [3,4,5,2,1]).empty?
#=> false

Answer 2

test = primary.dup
secondary.all? { |e| test.index(e).tap { |i| test.delete_at(i) if i } }
primary, secondary = [1, 2, 3], [2, 2]
#⇒ false
primary, secondary = [1, 2, 2, 3], [2, 2, 1]
#⇒ true
What’s being done here:
we iterate secondary, claiming that all blocks should return true
on each subsequent iteration we
immediately return false breaking the loop if there is no such element in primary
otherwise we mutate the copy of primary, removing the element already checked.
The only trick here is using Object#tap to always return true when element found. The element in the primary might be falsey, Array#delete returns the element deleted and we might accidentally return falsey, mistakenly breaking a loop in such a case. We should return true to all? loop as soon as we have the element found, hence tap.
The input to verify that this is the only correct answer here so far:
primary, secondary = [1, 2, 2, 3, nil, nil], [2, 2, 1, nil, nil]
#⇒ true
primary, secondary = [1, 2, 2, 3, nil], [2, 2, 1, nil, nil]
#⇒ false

Answer 3

primary = [1,2,3]
secondary = [2,3]
primary.each_cons(secondary.size).include?(secondary)
Enumerable#each_cons takes chunks of the array and iterates by one for each group.
Enumerable is awesome!
Read the Enumerable docs, I learn something new every time.

Answer 4

a = [5, 1, 6, 14, 2, 8]
b = [2, 6, 15]
a - b
=> [5, 1, 14, 8]
b - a
=> [15]
#this is what you need
(b - a).empty?
=> false

Answer 5

Here solution
primary=[1,2,3]
secondary=[2,3]
secondary.all? { |e| primary.include?(e) }

Answer 6

To check if an array is present inside another array, just use the include? method,
primary = [1,2,3,[1,2]]
secondary = [2,3]
result = primary.include? secondary
# returns false as [2,3] is not present
primary = [1,2,3,[1,2]]
secondary = [1,2]
result = primary.include? secondary
# returns true as [1,2] is present
To check if the elements of secondary array are present inside the primary array, takes care of the duplicate elements also:
result = (secondary.select {|i| secondary.count(i)<=primary.count(i)}.length == secondary.length)
primary, secondary = [1, 2, 3], [2, 2]
# returns false
primary, secondary = [1, 2, 2, 3], [2, 2, 1]
# returns true

Answer 7

a1 = [5, 3, 9, 7, 8, 7, 1, 7]
a2 = [1, 9, 5, 7, 5]
It will check elements of a2 are present in a1 or not,
a2.all?{ |i| a1.include? i } #=> true

Answer 8

Using
secondary.all? { |e| primary.include?(e) }
Use Intersection
(primary & secondary).size == secondary.uniq.size
If any element of secondary to be present in primary
(primary & secondary).present?
Hope it helps