1.字符串
定义：字符串就是一系列字符。在Python中用引号括起来的都是字符串
注意：引号可以是双引号，也可以是单引号，这种灵活性让你能够在字符串中包含引号和撇号
Exercise:
message_double = "this is double quotation marks demo "
message_single = 'this is single quotation mark demo'
print(message_double)
print(message_single)
需谨记：创建Python文件需要记得.py
Exercise
exercise_1 = ' i told my friend ,"python is my favorite language " '
exercise_2 = "the language 'Python' is named after Monty Python,not the snake"
exercise_3 = "one of python's strengths is its diverse and support community"
print(exercise_1)
print(exercise_2)
print(exercise_3)
知识点：
1.Python使用加号（+ ）来合并字符串
first_name = "yu"
last_name = 'yang'
full_name = first_name + " " + last_name
print(full_name)
2.制表符 \t
3.换行符 \n
4.去除空白 rstrip() 【右去除】 lstrip()【左去除】 strip() 【同时剔除】
4.1只能去除尾部空白，无法去除前面空白
4.2删除的变量需要存回变量中，才能保存。rstrip()不会保存修改后的变量
message = ' python '
print(message)
print(message.rstrip())