NM13

列表的用处很大，但只有你能访问里边的内容时它才能发挥出作用来。你已经学会了按顺序读出列表的内容，但如果你要得到第 5 个元素该怎么办呢?你需要知道如何访问列表中的元素。访问第一个元素的方法是这样的：animals = ['bear', 'tiger', 'penguin', 'zebra']bear = animals[0]你定义一个 animals 的列表，然后你用 0 来获取第一个

#!usr/bin/python# -*-coding:utf-8-*-people = 30cars = 40buses = 15if cars > people: print ("We should take the cars.")elif cars < people: print ("We should not take the cars.")else:

#!usr/bin/python# -*-coding:utf-8-*-people = 20cats = 30dogs = 15if people < cats: print ("Too many cats!The world is doomed")if people > cats: print ("Not many cats! The world is saved!")

#!usr/bin/python# -*-coding:utf-8-*-from sys import argvscript , user_name = argv prompt = '> 'print ("Hi %s, I'm the %s script." % (user_name, script))print ("I'd like to ask you a few questio

from sys import argvscript, first, second, third = argvprint ("The script is called:", script)print ("Your first variable is:", first)print ("Your second variable is:", second)print ("Your thir

age = input("How old are you? ")height = input("How tall are you? ")weight = input("How much do you weigh? ")print ("So, you're %r old, %r tall and %r heavy." % ( age, height, weight))运行

#!usr/bin/python# -*-coding:utf-8-*-True and Trueprint ("True")False and Trueprint ("False")1 == 1 and 2 == 1print ("False")"test" == "test"print ("True")1 == 1 or 2 != 1print ("True")Tru

童话里经常会看到英雄打败恶人的故事，而且故事里总会有一个类似黑暗森林的场景——要么是一个山洞，要么是一篇森林，要么是另一个星球，反正是英雄不该去的某个地方。当然，一旦反面角色在剧情中出现，你就会发现英雄非得去那片破森林去杀掉坏人。当英雄的总是不得不冒着生命危险进到邪恶森林中去。你很少会碰到这样的童话故事，说是英雄机智地躲过这些危险处境。你从不会听英雄说：“等等，如果我把白富美留

#!usr/bin/python# -*-coding:utf-8-*-import randomfrom urllib import urlopenimport sysWORD_URL = "http://learncodethehardway.org/words.txt"WORDS = []PHRASES = { "class ###(###):": "

#!usr/bin/python# -*-coding:utf-8-*-from sys import argvscript, filename = argv#获取参数 给script赋值ex15.py filename赋值ex15_sample.txt txt = open(filename)#打开 ex15_sample.txt文本print ("Here's your

#!usr/bin/python# -*-coding:utf-8-*-from sys import argvscript , filename = argvprint ("We're going to arase %r." % filename) # 打印 We're going to arase test.txtprint ("If you don't want

#!usr/bin/python# -*-coding:utf-8-*-from sys import argvfrom os.path import existsscript , from_file , to_file = argv# 定义值 script=lx0017.py from_file=test.txt to_file=copied.txtprint ("Copt

#!usr/bin/python# -*-coding:utf-8-*-i = 0numbers = []while i < 6: print ("At the top i is %d" %i) numbers.append(i) i = i + 1 print ("Numbers now: ", numbers) print ("At the bottom i is %d

#!usr/bin/python# -*-coding:utf-8-*-def add(a,b): print ("ADDING %d + %d" % (a,b)) return a + bdef subtract(a,b): print ("SUBTRACTING %d - %d" % (a,b)) return a - bdef multiply(a,b): print

#!usr/bin/python# -*-coding:utf-8-*-from sys import argvscript , input_file = argvdef print_all(f): print (f.read())#新建print_all函数 定义print (f.read())为函数代码def rewind(f): f.seek(0)#新建rewind

Python 软件包的安装你需要预先安装一些软件包，不过问题就来了。我的本意是让这本书越清晰越干净越好，不过安装软件的方法是在是太多了，如果我要一步一步写下来，那 10 页都写不完，而且告诉你吧，我本来就是个懒人。所以我不会提供详细的安装步骤了，我只会告诉你需要安装哪些东西，然后让你自己搞定。这对你也有好处，因为你将打开一个全新的世界，里边充满了其他人发布的 Python 软件。接下来

#!usr/bin/python# -*-coding:utf-8-*-the_count = [1, 2, 3, 4, 5]fruits = ['apples', 'oranges', 'pears', 'apricots']change = [1, 'pennies', 2, 'dimes', 3, 'quarters']for number in the_count: pri

#!usr/bin/python# -*-coding:utf-8-*-def cheese_and_crackers(cheese_count,boxes_of_crackers): print ("You have %d cheeses!" % cheese_count) print ("You have %d boxes_of_crackers!" % boxes_of_crack

#!usr/bin/python# -*-coding:utf-8-*-def print_two(*args): arg1,arg2 = args print ("arg1: %r,arg2: %r" % (arg1, arg2))def print_two_again(arg1,arg2): print ("arg1: %r,arg2: %r" % (arg1,arg2))

一、列表一组有序项目的集合。可变的数据类型【可进行增删改查】列表是以方括号“[]”包围的数据集合，不同成员以“,”分隔。列表中可以包含任何数据类型，也可包含另一个列表列表可通过序号访问其中成员二、元组不可变序列元组是以圆括号“()”包围的数据集合，不同成员以“,”分隔与列表不同：元组中数据一旦确立就不能改变三、字典键值对的集合(map)字典是以大括号“{

#!usr/bin/python# -*- coding:utf8 -*-print ("How old are you?"),age = input()print ("How tall are you?"),height = input("")print ("How much do you weight?"),weight = input()print ("So , you'r

#!usr/bin/python# -*- coding:utf8 -*-tabby_cat = "\tI'm tabbed in."persian_cat = "I'm split\non a line."backslash_cat = "I'm \\ a \\ cat."fat_cat = """I'll do a list:\t* Cat food\t* Fishies\

#!usr/bin/python# -*- coding:utf8 -*-# Here's somt new strange stuff, remember type it exactly.days = "Mon Tue Wed Thu Fri Sat Sun"months = "Jan\nFeb\nMar\nApr\nMay\nJun\nJul\nAug"print ("Here

#!usr/bin/python# -*-coding:utf-8-*-class TheThing(object): def __init__(self): self.number = 0 def some_function(self): print("I got called.") def add_me_up(self, mo

Keywords(关键字)anddelfromnotwhileaselifglobalorwithassertelseifpassyieldbreakexceptimportprintclassexecinraisecontinuefinallyisreturndefforlam

#!usr/bin/python# -*-coding:utf-8-*-def break_words(stuff): """This function will break up words for us.""" """ split()函数 语法：str.split(str="",num=string.count(str))[n] 参数说明： str:表示为分隔符，默认为空格，

print ("hello world")print ("hello Again")print ("I like typing this.")print ("This is fun.")print ('Yay! Printing')print ("I'd much rather you 'not'.")print ('I "said" do not touch this.)

#!usr/bin/python# -*-coding:utf-8-*-print ("Let's practice everything.")print ("You\'d need to know \'bout escape with \\ that do \n newlines and \t tabs.")poem = """\tThe lovely worldwith log

If 语句的规则每一个“if 语句”必须包含一个 else.如果这个 else 永远都不应该被执行到，因为它本身没有任何意义，那你必须在 else 语句后面使用一个叫做 die 的函数，让它打印出错误信息并且死给你看，这和上一节的习题类似，这样你可以找到很多的错误。“if 语句”的嵌套不要超过 2 层，最好尽量保持只有 1 层。 这意味着如果你在 if 里边又有了一个 if，那你就需要

#!usr/bin/python# -*-coding:utf-8-*-from sys import exitdef gold_room(): print("This room is full of gold. How much do you take?") next = input("> ") if "0" in next or "1" in next: how_muc

在网上阅读代码。这个任务初看会觉得很艰巨。我将直接把你丢到深水区呆几天，让你竭尽全力去读懂实实在在的项目里的代码。这节练习的目的不是让你读懂，而是让你学会下面的技能：找到你需要的 Python 代码。通读代码，找到文件。尝试理解你找到的代码。以你现在的水平，你还不具备完全理解你找到的代码的能力，不过通过接触这些代码，你可以熟悉真正的编程项目会是什么样子。当你做这节练习时，你可以

有一个重要的概念你需要弄明白，那就是“类(class)”和“对象(object)”的区别。问题在于，class 和 object 并没有真正的不同。它们其实是同样的东西，只是在不同的时间名字不同罢了。我用禅语来解释一下吧：鱼和泥鳅有什么区别?这个问题有没有让你有点晕呢?说真的，坐下来想一分钟。我的意思是说，鱼和泥鳅是不一样，不过它们其实也是一样的是不是?泥鳅是鱼的一种，所以说没什么不同，不

#!usr/bin/python# -*-coding:utf-8-*-states = { "Oregon":"OR", "Floriad":"FL", "California":"CA", "New York":"NY", "Michigan":"MI"}cities = { "CA":"San Francisco", "MI":"Detroit", "FL":"J

你已经差不多完成这本书的前半部分了，不过后半部分才是更有趣的。你将学到逻辑，并通过条件判断实现有用的功能。在你继续学习之前，你有一道试题要做。这道试题很难，因为它需要你修正别人写的代码。当你成为程序员以后，你将需要经常面对别的程序员的代码，也许还有他们的傲慢态度，他们会经常说自己的代码是完美的。这样的程序员是自以为是不在乎别人的蠢货。优秀的科学家会对他们自己的工作持怀疑态度，同样，优秀的程

#!usr/bin/python# -*- coding:utf8 -*-formatter = "%r %r %r %r"print (formatter % (1 , 2 , 3 , 4))print (formatter % ("one" , "two" , "three" , "four"))print (formatter % (True , False , False ,

#!usr/bin/python# -*- coding:utf8 -*-x = "There are %d types of people." %10binary = "binary"do_not = "don't"y = "Those who know %s and those who %s." % (binary , do_not)print (x)print (y)p

#!usr/bin/python# -*- coding:utf8 -*-print ("Mary had a little lamb.")print ("Its fleece was white as %s." % "snow")print ("And everywhere that Mary went.")print ("." * 10 ) #what'd that do?en

#!usr/bin/python# -*- coding:utf8 -*- my_name = "Zed A. Shaw"my_age= 35 #not a liemy_height = 74 #inchesmy_weight = 180 #lbsmy_eyes = "Blue"my_teeth = "White"my_hair = "Brown"print ("Let's

#!usr/bin/python# -*- coding:utf8 -*- cars = 100space_in_a_car = 4.0drivers = 30passengers = 90cars_not_driven = cars - driverscars_driven = driverscarpool_capacity = cars_driven * space_in_a

#!usr/bin/python# -*- coding:utf8 -*-# 打印功能 我将数我的小鸡们print ("I will now count my chickens")# 打印功能 母鸡20+30*6print ("Hens" , 25 + 30 * 6)# 打印功能 Roosters公鸡 100-25*3%4print ("Rppsters" , 100 - 25 *