Ruby 學習（七）雜湊型別Hash

新增新的健值對

獲取key對應的value

修改健值對 `hash[key]=value`

刪除預設值

遍歷包含判斷

反轉key和value `hash.invert`

獲取拼接

內容替換 `hash.replace(other_hash)`

例子

colors =

months = hash.new

months = 

puts months

months = 

puts months.length

2

months = 

puts months.empty?

false

months = 

months.store("3", "march")
puts months

months = 

months.store("3", "march")
months["4"] = "april"
puts months

months = 

puts months["1"] # january
puts months["3"] # 空nil

months = 

months["1"] = "new"
months["3"] = "march"
puts months

months = 

months.clear
puts months

{}

months = 

months.delete("1")
puts months

months = 

months.delete_if do |key, value|
key == "1"
endputs months

months = 

months.default = "default_value"

months = 

months.default = "default_value"
puts months.default("1")

default_value

months = 

months.each do |key, value|
puts "key: #, value: #"
end

key: 1, value: january

key: 2, value: february

months = 

months.each_key do |key|
puts "key: #"
end

key: 1

key: 2

months = 

months.each_value do |value|
puts "value: #"
end

value: january

value: february

months = 

res = months.select 
puts res

hash.has_key?(key)

hash.include?(key)
hash.key?(key)
hash.member?(key)

months = 

puts months.key?("2") # true
puts months.has_key?("1") # true
puts months.include?("3") # false
puts months.member?("4") # false

方法

hash.has_value?(value)

hash.value?(value)

例子

months = 

puts months.has_value?("january") # true
puts months.has_value?("march") # false

months = 

puts months.invert

months = 

puts months.keys

1

2

months = 

puts months.values

january

february

months = 

months2 = 
puts months.merge(months2)

months = 

months2 = 
puts months.replace(months2)

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