Hashes in Ruby

Faq.txt

Q1) Difference between update function and merge function ?
ans: Update combine 2 hashes in a destructive way with update or with no overwriting whereas merge function will just merge the two hash without overwritting

Q2) Can we convert hash from any array?
ans: No we can't ,for an array to convert to hash ,the number of elements in the array should be even.

Q3) How to access both key and value
ans: hash_name.each do|key,value|
     end
     
Q4) How to set default value in hash while creating?
ans: We use Hash.new("default value")

Mcq.txt

Q1) What will be the output of this statement ?
    hash=Hash.new("no such key")
    hash["pep"]="coder" 
    puts hash["coder"]

a) pep
b) nil
c) no such key
d) none of the above

ans: c)no such key

Q2) What function is use to remove a key value pair in hash

a) hash.remove(key)
b) key.remove(hash)
c) hash.delete(key)
d) hash_name.delete(key)

ans: d) hash_name.delete(key)

Q3) What will be the output of this statement ?
      
      h2=Hash["ko","po","lo","io"]
      h3 = Hash["Lisa Morel", "Aquagirl", "Betty Kane", "Batgirl"]
      h3.update(h2)
      puts h3
 
 a) {"ko","po","lo","io"}
 b) {"Lisa Morel", "Aquagirl", "Betty Kane", "Batgirl"}
 c) {"Lisa Morel"=>"Aquagirl", "Betty Kane"=>"Batgirl", "ko"=>"po", "lo"=>"io"}
 d) none of the above
 
 ans: d){"Lisa Morel"=>"Aquagirl", "Betty Kane"=>"Batgirl", "ko"=>"po", "lo"=>"io"}
 
 Q4) What will this statement give :
      
      h3 = Hash["A", "B", "C", "D","E"]
      puts h3["A"]
      
 a) "B"
 b) "A"
 c) error
 d) nil
 
 ans: c)error