Hackerrank Ruby Hash - Addition, Deletion, Selection Solution
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In this challenge, we will show you ways in which we can add key-value pairs to Hash objects, delete keys from them, and retain them based on a logic.
Consider the following Hash
object:
h = Hash.new
h.default = 0
A new key-value pair can be added using or the store
method
h[key] = value
or
h.store(key, value)
An existing key can be deleted using the delete
method
h.delete(key)
For destructive selection and deletion, we can use keep_if
and delete_if
as seen in Array-Selection
> h = {1 => 1, 2 => 4, 3 => 9, 4 => 16, 5 => 25}
=> {1 => 1, 2 => 4, 3 => 9, 4 => 16, 5 => 25}
> h.keep_if {|key, value| key % 2 == 0} # or h.delete_if {|key, value| key % 2 != 0}
=> {2 => 4, 4 => 16}
Note
For non-destructive selection or rejection, we can use select
, reject
, and drop_while
similar to Array-Selection
In this challenge, a hash object called hackerrank
is already created. You have to add
- A key-value pair [543121, 100] to the
hackerrank
object usingstore
- Retain all key-value pairs where keys are Integers ( clue : is_a? Integer )
- Delete all key-value pairs where keys are even-valued.
Solution in ruby
Approach 1.
hackerrank.store(543121,100)
hackerrank.keep_if {|a| a.is_a? Integer}
hackerrank.delete_if {|a| a.even?}
Approach 2.
hackerrank[543121] = 100
hackerrank.keep_if {|key, value| key.is_a? Integer}
hackerrank.delete_if {|key, value| key%2==0}
Approach 3.
# Enter your code here.
hackerrank[543121]=100
hackerrank.keep_if {|k,v| k.is_a? Integer }
hackerrank.delete_if {|k,v| k%2 == 0}