In this HackerRank Ruby Hash - Addition, Deletion, Selection problem solution 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 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 using store
Retain all key-value pairs where keys are Integers ( clue : is_a? Integer )
Delete all key-value pairs where keys are even-valued.
Problem solution.
# Enter your code here. hackerrank.store(543121,100) hackerrank.keep_if {|a,b| a.is_a? Integer } hackerrank.delete_if {|a,b| a.even? }
Second solution.
# Enter your code here. hackerrank.store(543121, 100) hackerrank.keep_if { | k, v| k.is_a? Integer } hackerrank.delete_if { | k, v| k % 2 == 0 }
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