今天接触了Mermaid和PlantUML，这俩看起来都是用来写流程图的。有时间学学语法看看。。。

DAY-3（二补）：

在列表基础上开始学习for循环：

1. for循环基本用法

# 命名约定举例：
# for cat in cats:
# for dog in dogs:
# for item in list_of_items:

magicians = ['alice','david','carolina']
for magician in magicians:
    print (magician)
# 将输出：
# alice
# david
# carolina

2. for循环中执行更多操作

magicians = ['alice','david','carolina']
for magician in magicians:
    print (f"{magician.title()},that was a great tricks!")
    print (f"I can't wait to see your next trick, {magician.title()}.\n")
print ("Thank you, everyone. That was a great magic show!")
# 将输出：
# Alice,that was a great tricks!
# I can't wait to see your next trick, Alice.

# David,that was a great tricks!
# I can't wait to see your next trick, David.

# Carolina,that was a great tricks!
# I can't wait to see your next trick, Carolina.

# Thank you, everyone. That was a great magic show!

# 使用 for 循环处理数据，是一种对数据集执行整体操作的不错方式。例如，你可能使用 for 循环来初始化游戏——遍历角色列表，将每个角色都显示到屏幕上；然后在循环后面添加一些代码，在屏幕上绘制所有角色后显示一个 Play Now 按钮。

3. 小练习：

# 练习：想出至少三种有共同特征的动物，将其名称存储在一个列表中，再使用 for 循环将每种动物的名称打印出来
pets = ['cat','dog','chick','sheep','cow']
for pet in pets:
    print (f"A {pet.title()} would make a great pet.")
print ("Any of these animals would make a great pet!")
# 将输出：A Cat would make a great pet.
# A Dog would make a great pet.
# A Chick would make a great pet.
# A Sheep would make a great pet.
# A Cow would make a great pet.
# Any of these animals would make a great pet!

DAY-3（补充）：

主要学习了列表排序操作~

1. sort()方法对列表进行永久排序，传入reverse=True可以将排好的序倒过来。

cars = ['bmw','audi','toyota','subaru']
cars.sort()
print(cars)
# 将输出['audi', 'bmw', 'subaru', 'toyota']
# 现在，汽车是按字母顺序排列的，再也无法恢复到原来的排列顺序。
# sort()方法中传入reverse=True可以反方向排列
cars.sort(reverse=True)
print(cars)
# 将输出['toyota', 'subaru', 'bmw', 'audi']
# 现在，汽车是按字母顺序倒序排列的，再也无法恢复到原来的排列顺序。

2. sorted()函数对列表进行临时排序，同上可以传入reverse=True进行倒序。

cars = ['bmw', 'audi', 'toyota', 'subaru']
print ('Here is the original list:')
print (cars)

print ('\nHere is the sorted list:')
print (sorted(cars))

print ('\nHere is the original list again:')
print (cars)
'''将输出：
Here is the original list:
['bmw', 'audi', 'toyota', 'subaru']

Here is the sorted list:
['audi', 'bmw', 'subaru', 'toyota']

Here is the original list again:
['bmw', 'audi', 'toyota', 'subaru']
'''
# 在调用 sorted() 函数后，列表元素的排列顺序并没有变。
# 同上，向sorted()函数传入reverse=True可倒序排序
# 注意：当所有值不全是小写时，字母排序更复杂。在确定排列顺序时，有多种解读大写字母的方式，此时要指定准确的排列顺序，可能会比这里所做的更加复杂。然而，大多数排序方式是以本节介绍的知识为基础的。

3. reverse()方法可以反转列表元素的排列顺序（不是按字母顺序倒序排列，而是单纯将原列表元素进行倒序操作）

cars = ['bmw', 'audi', 'toyota', 'subaru']
print (cars)
cars.reverse()
print (cars)
# 将输出：
# ['bmw', 'audi', 'toyota', 'subaru']
# ['subaru', 'toyota', 'audi', 'bmw']

4. len()函数获得列表长度

cars = ['bmw', 'audi', 'toyota', 'subaru']
print (len(cars))
# 将输出4
# 在需要完成如下任务时，len() 很有用：明确还有多少个外星人未被消灭，确定需要管理多少项可视化数据，计算网站有多少注册用户，等等。

昨天的忘记总结了，今天补上

/

DAY-2：

1、+ - * / **加减乘除、乘方运算

a = 3/3

输出a为3.0，将任意两个数相除，结果总是浮点数

a = 1+2.0

输出3.0，一个操作数是浮点数，结果总是浮点数

a = 114_000_000_000

下划线给数分组，打印不会显示下划线

a,b,c=11,45,14

多变量赋值

MAX = 114514

保持不变的常亮，通常全大写字母来命名

DAY-3

今天开始学列表

列表及其打印

bicycle = ['trek','cannondale','redline','specialized']
print(bicycle) 
# 输出['trek', 'cannondale', 'redline', 'specialized']

访问列表元素

# 访问列表元素
print(bicycle[0]) 
# 输出trek，结果干净、整洁（无方括号），注意索引从0开始（索引为0则访问第一个元素，索引为1则访问第二个元素...）

# 结合title()方法
print(bicycle[0].title())
# 输出trek，title()方法使首字母大写

# 索引
print(bicycle[1],bicycle[3],bicycle[-1])
# 输出cannondale specialized specialized。
# 索引为-1，返回倒数第一个元素
# 索引为-2，返回倒数第二个元素...

# 用f字符串创建消息
message = f"My first bicycle was a {bicycle[2].title()}."
print(message)
# 将输出"My first bicycle was a Redline."

练习

# 练习
game = ['PVZ','minecraft','genshin']
message = f"{game[0].title()} and {game[1].title()} are my favourite games, {game[2].title()} is my favourite game too!"
print(message)
# 输出Pvz and Minecraft are my favourite games, Genshin is my favourite game too!

修改列表元素

# 修改列表元素
motorcycles = ['honda','yamaha','suzuki']
print (motorcycles)
motorcycles[0] = 'ducati' # 通过索引修改列表元素。
print (motorcycles)

append()方法追加元素

motorcycles = ['honda','yamaha','suzuki']
motorcycles.append('ducati') 
print (motorcycles) # 将输出['honda', 'yamaha', 'suzuki', 'ducati']

insert()方法插入元素

motorcycles = ['honda','yamaha','suzuki']
motorcycles.insert(0,'ducati') # 将新元素插入到索引为0的位置，后边元素均后移一个位置
print (motorcycles) # 将输出['ducati', 'honda', 'yamaha', 'suzuki']

del语句删除元素

motorcycles = ['ducati', 'honda', 'yamaha', 'suzuki']
del motorcycles[0] # 删除第一个元素
print (motorcycles) # 将输出['honda', 'yamaha', 'suzuki']

pop()方法删除元素——弹出

motorcycles = ['honda','yamaha','suzuki']
pop_motor = motorcycles.pop() # 弹出最后的元素suzuki并赋给变量pop_motor
print (pop_motor) # 将输出suzuki
motorcycles = ['honda','yamaha','suzuki']
pop_motor = motorcycles.pop(1) # 弹出第二个元素并赋给变量pop_motor
print (pop_motor) # 将输出yamaha

如果要从列表中删除一个元素，且不再以任何方式使用它，就使用 del 语句；
如果要在删除元素后继续使用它，就使用 pop() 方法。

remove()方法：根据值删除元素

motorcycles = ['honda','yamaha','suzuki']
too_expensive = 'yamaha'
motorcycles.remove(too_expensive)
print (motorcycles)
print (f"\nA {too_expensive.title()} is too expensive for me.")
# 将输出['honda', 'suzuki']
# 将输出A Yamaha is too expensive for me.

DAY-1：

1、打印Hello World！

2、方法：name.title()表示对name变量执行title()函数的操作

title()：将字符串各单词首字母变成大写

upper()、lower()将字符串全部字母变成大/小写

f字符串：通过把花括号内的变量替换为其值来设置字符串的格式

例：

a=1

b=2

c=f"{a}{b}" # c='12'

\t：添加制表符

\n：添加换行符

strip()方法：删去字符串两端的空白，lstrip()和rstrip()分别删去左、右的空白

removeprefix()方法：删去前缀，括号里放要删的前缀