（一）if 语句

if语句

people = 20
cats = 30
dogs = 15if people < cats:print("Too many cats,The world is doomed")
if people > cats:print("Not mangy cats! The world is saved!")if people < dogs:print("The world is drooled on!")if people >dogs:print("The world is dry!")dogs +=5if people >=dogs:print("People are greater than or equal to dogs.") if people <=dogs:print("People are less than or equal to dogs.")if people ==dogs:print("People are dogs.")

运行的结果：

Too many cats,The world is doomed
The world is dry!
People are greater than or equal to dogs.
People are less than or equal to dogs.
People are dogs.
[Finished in 1.4s]

上面有if代码块，if代码块创建了一个分支；按照python语法要求必须缩进4个空格，这是告诉python创建了新的代码块。如果添加上elif,else等。

Else和if

people = 30
cars =40
trucks = 15if cars > people:print("We should take the cars.")
elif cars < people:print("We should not take the cars.")
else:print("We cat't decide.")if trucks >cars:print("That too many trucks!")
elif trucks < cars:print("Maybe we could take the trucks!")
else:print("We still can't decide!")if people > trucks:print("Alright, let's just take the trucks.")
else:print('Fine, let\'s  stay home then')

运行的结果：

We should take the cars.
Maybe we could take the trucks!
Alright, let's just take the trucks.
[Finished in 132ms]

注意：if-elif-else语句，python从顶部开始，只运行第一个True的代码块，其他的就不运行了；所以如果需要每个条件都需要做出判断的情况下，可以使用多个if条件，像上面的多个if语句。

IF嵌套使用

print("""You enter a dark room with two doors.
Do you go through door #1 or door #2?""")door = input(">")if door =='1':print("There's a giant bear here eating a cheese cake.")print("What do you do?")print("1,Take the  cake.")print("2,Scream at the bear.")bear = input(">")if bear =='1':print("The bear eats your face off.Good job!")elif bear =='2':print("The bear eats your legs off.Good job!")else:print(f"Well,doing {bear} is probably better.")print("Bear runs away.")elif door=='2':print("You stare into the endless abyss at Cthulhu's retina.")print("1,Blueberries.")print("2,Yellow jacket clothespins.")print("3,Understanding revolvers yelling melodies.")insanity = input(">")if insanity =='1'or insanity =='2':print("Your body survies powered by a mind of jello.")print("Good job!")else:print("You stumble around and fall on a knife and die. Good job!")

运行的结果：

You enter a dark room with two doors.
Do you go through door #1 or door #2?
>1
There's a giant bear here eating a cheese cake.
What do you do?
1,Take the  cake.
2,Scream at the bear.
>2
The bear eats your legs off.Good job!

sublime text无法完成交互，使用终端解决交互的问题。

（二）FOR语句

the_count = [1,2,3,4,5]
fruits = ['apples','oranges','pears','apricots']
change = [1,'pennies',2,'dimes',3,'quarters']#this first kind of for-loop goes through a list
for number in the_count:print(f"This is count {number}")#same as above
for fruit in fruits:print(f"A fruit of type {fruit}")# also we can go through mixed lists too
# notice we have to use {} since we don't know what's in it
for i in change:print(f"I got {i}")#we can also build lists, first start with an empty one
elements = []# then use the range function to do 0 to 5 counts
for i in range(0,6):print(f"Adding {i} to the list.")
# append is a function that lists understandelements.append(i)# now we can print them out too
for i in elements:print(f"Elements was: {i}")

运行的结果：

This is count 1
This is count 2
This is count 3
This is count 4
This is count 5
A fruit of type apples
A fruit of type oranges
A fruit of type pears
A fruit of type apricots
I got 1
I got pennies
I got 2
I got dimes
I got 3
I got quarters
Adding 0 to the list.
Adding 1 to the list.
Adding 2 to the list.
Adding 3 to the list.
Adding 4 to the list.
Adding 5 to the list.
Elements was: 0
Elements was: 1
Elements was: 2
Elements was: 3
Elements was: 4
Elements was: 5
[Finished in 116ms]

注意for 语句的遍历，以及函数range的用法，注意点。

（三）while语句

i = 0
numbers = []while i < 6:print(f"At the top i is {i} ")numbers.append(i)i +=1print("Numbers now:",numbers)print(f"At the bottom i is {i}")
print("The numbers:")
for i in numbers:print(i)

运行的结果：

At the top i is 0
Numbers now: [0]
At the bottom i is 1
At the top i is 1
Numbers now: [0, 1]
At the bottom i is 2
At the top i is 2
Numbers now: [0, 1, 2]
At the bottom i is 3
At the top i is 3
Numbers now: [0, 1, 2, 3]
At the bottom i is 4
At the top i is 4
Numbers now: [0, 1, 2, 3, 4]
At the bottom i is 5
At the top i is 5
Numbers now: [0, 1, 2, 3, 4, 5]
At the bottom i is 6
The numbers:
0
1
2
3
4
5
[Finished in 133ms]

分支和函数

from sys import exit
def gold_room():print("This room is full of gold. How much do you take?")choice = input('>')if '0' in choice or '1' in choice:how_much = int(choice)else:dead("Man,learn to type a number.")if how_much <50:print("Nice,you're not greedy,you win!")exit(0)else:dead("You greedy bastard！")
def bear_room():print('There is a bear here.')print("The bear has a bunch of honey.")print("The fat bear is in front of another door.")print("How are you going to move the  bear?")bear_moved =Falsewhile True:choice = input('>')if choice =='take honey':dead("The bear looks at you then slaps your face")elif choice =="taunt bear" and not bear_moved:print("The bear has moved from the door.")print("You can go through it now.")bear_moved = Trueelif choice=="taunt bear" and bear_moved:dead("The bear gets pissed off and chews your leg.")elif choice=="open door" and bear_moved:gold_room()else:print("I got no idea what that means.")def cthulhu_room():print("Here you see the great evil Cthulhu")print("He,it,whatever strats at you and you go insane")print("Do you flee your life or eat your head?")choice = input(">")if 'flee' in choice:strat()elif 'head' in choice:dead("Well that was tasty!")else:cthulhu_room()def dead():print(why,"Good job!")exit(0)def start():print("You are in a dark room.")print("There is a door to your right and left.")print("Which one do you take?")choice = input('>')if choice =='left':bear_room()elif choice =='right':cthulhu_room()else:dead("You stumble around the room until you starve.")start()

运行的结果：

You are in a dark room.
There is a door to your right and left.
Which one do you take?
>left
There is a bear here.
The bear has a bunch of honey.
The fat bear is in front of another door.
How are you going to move the  bear?
>taunt bear
The bear has moved from the door.
You can go through it now.
>open door
This room is full of gold. How much do you take?
>1000
You greedy bastard！ Good job!

理解这个游戏中的逻辑。

第六章、FOR、IF和while相关推荐

王道考研计算机网络笔记第六章：应用层
本文基于2019 王道考研计算机网络: 2019 王道考研计算机网络个人笔记总结第一章:王道考研计算机网络笔记第一章:概述&计算机网络体系结构第二章:王道考研计算机网络笔记第 ...
JavaScript高级程序设计（第3版）第六章读书笔记
第六章面向对象的程序设计 1. 数据属性 [[Configurable]]:表示能否通过delete删除属性从而重新定义属性.默认值为true. [[Enumerable]]:表示能否通过for-i ...
数字图像处理——第六章彩色图像处理
数字图像处理--第六章彩色图像处理文章目录数字图像处理--第六章彩色图像处理 1 彩色模型 1.1 RGB彩色模型 1.2 CMY 和CMYK彩色模型 1.3 HSI彩色模型 2 伪彩色图像处 ...
java三维滑雪,第六章三维数据空间分析方法.ppt
第六章三维数据空间分析方法 * * * * 可视性分析 * * 自然邻域法插值基本思路: 利用输入点及邻近栅格单元进行插值生成栅格表面. 方法: 利用输入数据点(样本点)为节点,建立Delauna ...
Knockout应用开发指南第六章：加载或保存JSON数据
原文:Knockout应用开发指南第六章:加载或保存JSON数据加载或保存JSON数据 Knockout可以实现很复杂的客户端交互,但是几乎所有的web应用程序都要和服务器端交换数据(至少为了本地 ...
ASP.NET2.0自定义控件组件开发第六章深入讲解控件的属性
深入讲解控件的属性持久化(一) 系列文章链接: ASP.NET自定义控件组件开发第一章待续 ASP.NET自定义控件组件开发第一章第二篇接着待续 ASP.NET自定义控件组件开发第一章第 ...
机器学习-第六章支持向量机(SVM)
机器学习-第六章支持向量机(SVM) D系鼎溜关注 2020.02.09 21:19:41字数 1,131阅读 458 6.1 间隔与支持向量开倍速观看视频之后,对课本所说的会更加了解. 支持向量 ...
第六章非编码RNA鉴定
第六章非编码RNA鉴定阅读量: 154 主要为RNA-seq相关知识,部分内容作笔记自查使用.如有错误或遗漏还请海涵,可评论或邮箱联系. 最后修改时间:2020-09-07 14:38:07 星 ...
谭浩强c语言第六章兔子数列,谭浩强 C语言第6章_循环.ppt
谭浩强 C语言第6章_循环第六章本章要点循环的基本概念不同形式的循环控制多重循环问题主要内容 6.1 概述 6.2 goto语句以及用goto语句构成循环 6.3 用while语句实现循 ...
北电ERS1600,8300,8600交换机的基本技术－第六章二层冗余技术（MLT,SMLT,IST）
第六章二层冗余技术(MLT,SMLT,IST) 这里只介绍北电独有的MLT ,SMLT 和IST.这些是二层的冗余协议: MLT:多链路中继,将多条链路模拟成一条链路 SMLT: 分离的多链路中继, ...

第六章、FOR、IF和while

（一）if 语句

if语句

Else和if

IF嵌套使用

（二）FOR语句

（三）while语句

分支和函数

第六章、FOR、IF和while相关推荐

最新文章

热门文章