Python编程入门到实践 - 笔记（ 4 章）-白红宇

Python编程入门到实践 - 笔记（ 4 章）

阅读量：6331 次

发布时间：2019-06-22

本文共 6583 字，大约阅读时间需要 21 分钟。

昨天下午又看了一遍第4章，今天早上自己来个总结吧。

复习内容如下：

通过 for 循环遍历表中内容以及在循环中打印和循环外打印

rang() 创建列表和设置步长

数字列表的简单统计

1）mix 最小

2）max 最大

3）sum 和

C语言风格的运算加 for 循环

列表中元素的切片，赋值列表

遍历元组以及元组的重新赋值

通过 for 循环遍历列表中的内容

---------------------------------------------------

magicians = ['alice', 'david', 'carolina']

for magician in magicians:

print(magician)

---------------------------------------------------

alice

david

carolina

在 for 循环中执行更多的操作，告诉每一位魔术师期待他的下一次表演

-----------------------------------------------------------------------------

magicians = ['alice', 'david', 'carolina']

for magician in magicians:

print(magician.title() + ", that was a great trick!")

print("I can't wait to see your next trick, " + magician.title() + ".\n")

------------------------------------------------------------------------------

Alice, that was a great trick!

I can't wait to see your next trick, Alice.

David, that was a great trick!

I can't wait to see your next trick, David.

Carolina, that was a great trick!

I can't wait to see your next trick, Carolina.

在 for 循环结束后执行一些操作

------------------------------------------------------------------------------

magicians = ['alice', 'david', 'carolina']

for magician in magicians:

print(magician.title() + ", that was a great trick!")

print("I can't wait to see your next trick, " + magician.title() + ".\n")

print("Thank you, everyone. That was a great magic show!")

-------------------------------------------------------------------------------

Alice, that was a great trick!

I can't wait to see your next trick, Alice.

David, that was a great trick!

I can't wait to see your next trick, David.

Carolina, that was a great trick!

I can't wait to see your next trick, Carolina.

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

range()创建数值列表

这里的 range() 只打印数字 1~4，range() 会在达到指定的第二个值时停止打印

----------------------------------------

for value in range(1,5):

print(value)

----------------------------------------

使用 range() 创建数字列表

------------------------------------

numbers = list(range(1,6))

print(numbers)

------------------------------------

[1, 2, 3, 4, 5]

range() 还可以在第三位指定步长

第三位指定 2，表示数字不断 +2 打印

--------------------------------------------

numbers = list(range(1,11,2))

print(numbers)

--------------------------------------------

[1, 3, 5, 7, 9]

将前 10 个整数平方加入到一个列表中

--------------------------------------------

squares = []

for value in range(1,11):

square = value ** 2

squares.append(square)

print(squares)

---------------------------------------------

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

对数字列表执行简单的统计

min 最小

max 最大

sum 和

--------------------------------------------

digits = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

print(min(digits))

print(max(digits))

print(sum(digits))

--------------------------------------------

C 语言风格的列表解析

------------------------------------------------------------

squares = [ value**2 for value in range(1,11) ]

print(squares)

------------------------------------------------------------

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

使用列表的一部分（切片）

取出列表的前三个元素

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print(players[0:3])

------------------------------------------------------------------------

['charles', 'martina', 'michael']

取出列表的第 2~4 个元素

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print(players[1:4])

-----------------------------------------------------------------------

['martina', 'michael', 'florence']

如果没有指定索引，python 会自动从头开始切

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print(players[:4])

-----------------------------------------------------------------------

['charles', 'martina', 'michael', 'florence']

中括号里面的第二位不指定，代表终止于列表末尾

打印从第三个到列表末尾的所有元素

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print(players[2:])

-----------------------------------------------------------------------

['michael', 'florence', 'eli']

打印列表中最后三个元素

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print(players[-3:])

-----------------------------------------------------------------------

['michael', 'florence', 'eli']

遍历切片

只遍历列表的部分元素，打印前三个元素

-----------------------------------------------------------------------

players = ['charles', 'martina', 'michael', 'florence', 'eli']

print("Here are the first three players on my team:")

for player in players[:3]:

print(player.title())

-----------------------------------------------------------------------

Here are the first three players on my team:

Charles

Martina

Michael

复制列表

通过 [ : ] 复制一个新列表

--------------------------------------------------------

my_foods = ['pizza', 'falafel', 'carrot cake']

friend_foods = my_foods[:]

print("My favorite foods are:")

print(my_foods)

print("\nMy friend's favorite foods are:")

print(friend_foods)

--------------------------------------------------------

My favorite foods are:

['pizza', 'falafel', 'carrot cake']

My friend's favorite foods are:

['pizza', 'falafel', 'carrot cake']

给两个列表分别添加元素，证明我们确实打印的是两个表

--------------------------------------------------------

my_foods = ['pizza', 'falafel', 'carrot cake']

friend_foods = my_foods[:]

my_foods.append('cannoli')

friend_foods.append('ice cream')

print("My favorite foods are:")

print(my_foods)

print("\nMy friend's favorite foods are:")

print(friend_foods)

--------------------------------------------------------

My favorite foods are:

['pizza', 'falafel', 'carrot cake', 'cannoli']

My friend's favorite foods are:

['pizza', 'falafel', 'carrot cake', 'ice cream']

元组

元组是用圆括号来标识

定义元组后可以用索引来访问其元素，就像访问列表元素一样

不能给元组中的元素赋值

------------------------------

dimensions = (200, 50)

print(dimensions[0])

print(dimensions[1])

------------------------------

200

遍历元组中的所有值

---------------------------------------

dimensions = (200, 50)

for dimension in dimensions:

print(dimension)

----------------------------------------

200

给元组的变量重新赋值

虽然不能修改元组中的元素，但是可以给元组的变量赋值，以此达到修改元组中元素的目的

----------------------------------------------

dimensions = (200, 50)

print("Original dimensions:")

for dimension in dimensions:

print(dimension)

dimensions = (100, 500)

print("\nModified dimensions:")

for dimension in dimensions:

print(dimension)

----------------------------------------------

Original dimensions:

200

Modified dimensions:

100

500

转载于:https://blog.51cto.com/aby028/1964821

你可能感兴趣的文章

mysql服务器的主从配置

查看>>

巧用AJAX技术，通过updatePanel控件实现局部刷新

ThinkPHP 3.2.x 集成极光推送指北

java中如何选择Collection Class--java线程（第3版）

查看>>

为运维人员插上腾飞更远的翅膀！

查看>>

Word 2003中编辑标记与格式标记大讨论

SQL Server vNext CTP1 on Linux

查看>>

1-为 Lync Server 2010 准备 Active Directory 域服务

查看>>

SELinux安全

查看>>

NetBackup下ORACLE恢复测试方案实例解析

查看>>

【有奖征文】“失业”程序员的苦辣酸甜

查看>>

IE9是如何被FireFox4超越全球市场份额的？

查看>>

linux bunzip2命令

查看>>