How to get the hash key and value in ruby?

How to get the hash value using hash key in ruby

a = {1=>"Active", -1=>"Inactive", 0=>"Under Review"} 

a[1] # 'Active'

a[-1] # 'Inactive'

a[0] # 'Under Review'

How to get the hash key using hash value in ruby 

a = {1=>"Active", -1=>"Inactive", 0=>"Under Review"} 

a.key('Active') #1

a.key('Inactive') #-1

a.key('Under Review') #0