关于hash的一些用法

java 代码

users_hash = {"tom" => "password0",
"adi" => "password1",
"aaron" => "password2" }

# The following line will not add anything to users_hash.
# But will return a hash that has users_hash and
# the new added entry.
users_hash.merge({"sam1" => "password3"})

#The following line will modify users_hash by
#adding the new entry and return it
users_hash.merge!({"sam2" => "password3"})
# or you can make it like this
#users_hash.merge!("sam2" => "password3")

users_hash.each {  |key, value|
puts "Key is #{key} and value is #{value}"
}
cities = [
{"Name" => "los angeles", "State" => "CA"},
{"Name" => "las vegas", "State" => "NV"},
{"Name" => "miami", "State" => "FL"}
]

cities.map! { |c| c.merge!("Count" => 1) }

puts cities