Ruby学习中(哈希变量/python的字典, )

# 创建一个空的Hash
months = Hash.new
puts months
print(months[1])

# 创建一个具有默认值得Hash
months = Hash.new( "month" )
# 或
months = Hash.new "month"
puts months
print(months[1])

输出结果：
{}
报错

{}
month

Python：
a = dict(a=1, b=2)  # 正确
print(a)
b = dict[a=1, b=2]  # 错误
print(b)
c = {["a", "b"]: 1} # 错误
print(c)

Ruby：
a = Hash(a=1, b=2)  # 错误
puts a
a = Hash["a" => 1, "b" => 2]  # 正确
puts a
b = Hash("a" => 1, "b" => 2)  # 正确
puts b
c = Hash("a": 1, "b": 2)  # 正确
puts c
d = Hash([1, "he"] => "hai")  # 正确
puts d

输出结果：
error
{"a"=>1, "b"=>2}
{"a"=>1, "b"=>2}
{:a=>1, :b=>2}
{[1, "he"]=>"hai"}

Python：
a = {"a": 1, "b": 2}
print(a["a"])

Ruby：
game = {"疾风剑豪" => "亚索", "流影之主" => "劫", "刀锋之影" => "泰隆"}
puts game
puts game["疾风剑豪"]
user = {name: "进不去啊", age: 18, gender: "男"}
puts user
puts user["name"] # nil
puts user[name]   # 报错
puts user[:name]

输出结果：
{"疾风剑豪"=>"亚索", "流影之主"=>"劫", "刀锋之影"=>"泰隆"}
亚索
{:name=>"进不去啊", :age=>18, :gender=>"男"}

error
进不去啊

str = "12345"
puts str
str1 = str.to_i     # 转整型
puts str1
str2 = str1.to_s    # 转字符串
puts str2
str3 = str1.to_f    # 转浮点
puts str3

str = "12345hei"
str1 = str.to_i
str2 = str.to_f
puts str1, str2
puts str1.class, str2.class

输出结果：
12345
12345.0
Integer
Float

str = "hei12345hei"
str1 = str.to_i
str2 = str.to_f
puts str1, str2
puts str1.class, str2.class

输出结果：
0
0.0
Integer
Float

str = "12345hei6789"
str1 = str.to_i
str2 = str.to_f
puts str1, str2
puts str1.class, str2.class

输出结果：
12345
12345.0
Integer
Float

str = "hei12345hei6789"
str1 = str.to_i
str2 = str.to_f
puts str1, str2
puts str1.class, str2.class

输出结果：
0
0.0
Integer
Float