Python编程：像计算机科学家一样思考

综合文档

需积分: 10 167 浏览量更新于2024-07-16 收藏 891KB PDF 举报

身份认证购VIP最低享 7 折!

领优惠券(最高得80元）

"Python_for_Software_Design_－_How_to_Think_Like_a_Computer_Scientist_（2009）.pdf.pdf" 《Python for Software Design - How to Think Like a Computer Scientist》是由Allen B. Downey编写的，旨在帮助读者通过Python编程语言来理解和实践计算机科学的基本思想。这本书由Olin College of Engineering的作者撰写，于2009年由Cambridge University Press出版。这本书的目的是使读者具备软件设计的基础知识，并培养他们像计算机科学家那样思考问题的能力。本书涵盖了以下关键知识点： 1. 基础编程概念：书中详细介绍了Python编程语言的基本语法，包括变量、数据类型（如整数、浮点数、字符串）、控制结构（如条件语句和循环）、函数以及模块的使用。 2. 问题解决与算法设计：作者鼓励读者学习如何分析问题并设计有效的算法来解决它们。这涉及了递归、分治策略和复杂度分析等核心概念。 3. 数据结构：书中讨论了不同的数据结构，如列表、元组、字典和集合，以及它们在实际编程中的应用。此外，还涵盖了列表推导式和迭代器等高级主题。 4. 面向对象编程：介绍Python的面向对象编程特性，包括类的定义、继承、封装和多态性，让读者了解如何构建可重用和模块化的代码。 5. 错误处理与调试：讲解了如何识别和处理程序中的错误，包括异常处理和调试技巧，帮助读者编写健壮的代码。 6. 文件操作：介绍了如何读写文件，以及如何处理文件输入输出，这是软件设计中常见的任务。 7. 软件工程原则：书中可能包含关于软件开发过程、版本控制、测试和文档编写等方面的内容，这些都是软件项目管理的关键部分。 8. 问题求解策略：书中可能会教授如何分析问题、分解问题和设计解决方案，这对于成为一名成功的计算机科学家至关重要。 9. 计算机科学理论基础：虽然可能不会深入到计算机科学的每一个领域，但可能会涉及到计算理论的一些基本概念，如递归、图灵机和计算复杂性。 10. 实践应用：通过一系列的实例和练习，鼓励读者将所学知识应用于实际问题，从而加深对概念的理解。《Python for Software Design》是一本面向初学者的全面教程，它不仅教授Python编程语言，更注重培养解决问题和设计软件的能力，为读者进入计算机科学领域打下坚实基础。书中的内容丰富多样，涵盖了从基本编程概念到高级软件设计原理的多个层面，适合那些希望通过Python学习计算机科学思维方式的读者。

资源详情

资源推荐

The Way of the Program

The goal of this book is to teach you to think like a computer scientist. This way

of thinking combines some of the best features of mathematics, engineering, and

natural science. Like mathematicians, computer scientists use formal languages to

denote ideas (speciﬁcally computations). Like engineers, they design things, assem-

bling components into systems and evaluating tradeoffs among alternatives. Like

scientists, they observe the behavior of complex systems, form hypotheses, and test

predictions.

The single most important skill for a computer scientist is problem solving. Problem

solving means the ability to formulate problems, think creatively about solutions,

and express a solution clearly and accurately. As it turns out, the process of learning

to program is an excellent opportunity to practice problem-solving skills. That’s why

this chapter is called “The way of the program.”

On one level, you will be learning to program, a useful skill by itself. On another

level, you will use programming as a means to an end. As we go along, that end will

become clearer.

1.1 THE PYTHON PROGRAMMING LANGUAGE

The programming language you will learn is Python. Python is an example of a high-

level language; other high-level languages you might have heard of are C, C++, Perl,

and Java.

There are also low-level languages, sometimes referred to as “machine languages”

or “assembly languages.” Loosely speaking, computers can only execute programs

written in low-level languages. So programs written in a high-level language have to

be processed before they can run. This extra processing takes some time, which is a

small disadvantage of high-level languages.

The advantages are enormous, however. First, it is much easier to program in a high-

level language. Programs written in a high-level language take less time to write,

欢迎加入非盈利Python编程学习交流QQ群783462347，群里免费提供500+本Python书籍！

2 The Way of the Program

they are shorter and easier to read, and they are more likely to be correct. Second,

high-level languages are portable, meaning that they can run on different kinds of

computers with few or no modiﬁcations. Low-level programs can run on only one

kind of computer and have to be rewritten to run on another.

Due to these advantages, almost all programs are written in high-level languages.

Low-level languages are used only for a few specialized applications.

Two kinds of programs process high-level languages into low-level languages: inter-

preters and compilers. An interpreter reads a high-level program and executes it,

meaning that it does what the program says. It processes the program a little at a

time, alternately reading lines and performing computations.

OUTPUT

SOURCE

CODE

INTERPRETER

A compiler reads the program and translates it completely before the program starts

running. In this context, the high-level program is called the source code, and the

translated program is called the object code or the executable. Once a program is

compiled, you can execute it repeatedly without further translation.

OUTPUT

CODE

OBJECT

EXECUTOR

CODE

SOURCE

COMPILER

Python is considered an interpreted language because Python programs are executed

by an interpreter. There are two ways to use the interpreter: interactive mode and

script mode. In interactive mode, you type Python programs and the interpreter

prints the result:

>>>1+1

The chevron, >>>, is the prompt the interpreter uses to indicate that it is ready. If

you type 1+1, the interpreter replies 2.

Alternatively, you can store code in a ﬁle and use the interpreter to execute the

contents of the ﬁle, which is called a script. By convention, Python scripts have

names that end with .py.

To execute the script, you have to tell the interpreter the name of the ﬁle. In a UNIX

command window, you would type python dinsdale.py. In other development

environments, the details of executing scripts are different. You can ﬁnd instructions

for your environment at the Python Website python.org.

欢迎加入非盈利Python编程学习交流QQ群783462347，群里免费提供500+本Python书籍！

1.3 What is Debugging 3

Working in interactive mode is convenient for testing small pieces of code because

you can type and execute them immediately. But for anything more than a few lines,

you should save your code as a script so you can modify and execute it in the future.

1.2 WHAT IS A PROGRAM?

A program is a sequence of instructions that speciﬁes how to perform a computa-

tion. The computation might be something mathematical, such as solving a system of

equations or ﬁnding the roots of a polynomial, but it can also be a symbolic compu-

tation, such as searching for and replacing text in a document or (strangely enough)

compiling a program.

The details look different in different languages, but a few basic instructions appear

in just about every language:

input: Get data from the keyboard, a ﬁle, or some other device.

output: Display data on the screen or send data to a ﬁle or other device.

math: Perform basic mathematical operations like addition and multiplication.

conditional execution: Check for certain conditions and execute the appropriate

sequence of statements.

repetition: Perform some action repeatedly, usually with some variation.

Believe it or not, that’s pretty much all there is to it. Every program you’ve ever used,

no matter how complicated, is made up of instructions that look pretty much like

these. So you can think of programming as the process of breaking a large, complex

task into smaller and smaller subtasks until the subtasks are simple enough to be

performed with one of these basic instructions.

That may be a little vague, but we will come back to this topic when we talk about

algorithms.

1.3 WHAT IS DEBUGGING?

Programming is error-prone. For whimsical reasons, programming errors are called

bugs and the process of tracking them down is called debugging.

Three kinds of errors can occur in a program: syntax errors, runtime errors, and

semantic errors. It is useful to distinguish between them in order to track them down

more quickly.

1.3.1 Syntax Errors

Python can only execute a program if the syntax is correct; otherwise, the interpreter

displays an error message. Syntax refers to the structure of a program and the rules

about that structure. For example, parentheses have to come in matching pairs, so

(1+2)is legal, but 8) is a syntax error.

In English, readers can tolerate most syntax errors, which is why we can read the

poetry of e. e. cummings without spewing error messages. Python is not so forgiving.

欢迎加入非盈利Python编程学习交流QQ群783462347，群里免费提供500+本Python书籍！

4 The Way of the Program

If there is a single syntax error anywhere in your program, Python will display an

error message and quit, and you will not be able to run your program. During the

ﬁrst few weeks of your programming career, you will probably spend a lot of time

tracking down syntax errors. As you gain experience, you will make fewer errors and

ﬁnd them faster.

1.3.2 Runtime Errors

The second type of error is a runtime error, so called because the error does not

appear until after the program has started running. These errors are also called

exceptions because they usually indicate that something exceptional (and bad) has

happened.

Runtime errors are rare in the simple programs you will see in the ﬁrst few chapters,

so it might be a while before you encounter one.

1.3.3 Semantic Errors

The third type of error is the semantic error. If there is a semantic error in your

program, it will run successfully in the sense that the computer will not generate any

error messages, but it will not do the right thing. It will do something else. Speciﬁcally,

it will do what you told it to do.

The problem is that the program you wrote is not the program you wanted to write.

The meaning of the program (its semantics) is wrong. Identifying semantic errors

can be tricky because it requires you to work backward by looking at the output of

the program and trying to ﬁgure out what it is doing.

1.3.4 Experimental Debugging

One of the most important skills you will acquire is debugging. Although it can

be frustrating, debugging is one of the most intellectually rich, challenging, and

interesting parts of programming.

In some ways, debugging is like detective work. You are confronted with clues, and

you have to infer the processes and events that led to the results you see.

Debugging is also like an experimental science. Once you have an idea about what is

going wrong, you modify your program and try again. If your hypothesis was correct,

then you can predict the result of the modiﬁcation, and you take a step closer to a

working program. If your hypothesis was wrong, you have to come up with a new

one. As Sherlock Holmes pointed out, “When you have eliminated the impossible,

whatever remains, however improbable, must be the truth” (A. Conan Doyle, The

Sign of Four).

For some people, programming and debugging are the same thing. That is, pro-

gramming is the process of gradually debugging a program until it does what you

want. The idea is that you should start with a program that does something and make

欢迎加入非盈利Python编程学习交流QQ群783462347，群里免费提供500+本Python书籍！

1.4 Formal and Natural Languages 5

small modiﬁcations, debugging them as you go, so that you always have a working

program.

For example, Linux is an operating system that contains thousands of lines of code,

but it started out as a simple program Linus Torvalds used to explore the Intel 80386

chip. According to Larry Greenﬁeld, “One of Linus’s earlier projects was a program

that would switch between printing AAAA and BBBB. This later evolved to Linux”

(The Linux Users’ Guide Beta Version 1).

Later chapters will make more suggestions about debugging and other programming

practices.

1.4 FORMAL AND NATURAL LANGUAGES

Natural languages are the languages people speak, such as English, Spanish, and

French. They were not designed by people (although people try to impose some

order on them); they evolved naturally.

Formal languages are languages that are designed by people for speciﬁc applica-

tions. For example, the notation that mathematicians use is a formal language that is

particularly good at denoting relationships among numbers and symbols. Chemists

use a formal language to represent the chemical structure of molecules. And most

importantly:

Programming languages are formal languages that have been designed to express

computations.

Formal languages tend to have strict rules about syntax. For example, 3 + 3 = 6

is a syntactically correct mathematical statement, but 3+=3$6 is not. H

Oisa

syntactically correct chemical formula, but

Zz is not.

Syntax rules come in two ﬂavors, pertaining to tokens and structure. Tokens are the

basic elements of the language, such as words, numbers, and chemical elements. One

of the problems with 3+=3$6 is that $ is not a legal token in mathematics (at least

as far as I know). Similarly,

Zz is not legal because there is no element with the

abbreviation Zz.

The second type of syntax error pertains to the structure of a statement, that is, the

way the tokens are arranged. The statement 3+=3$6 is illegal because even though

+ and = are legal tokens, you can’t have one right after the other. Similarly, in a

chemical formula the subscript comes after the element name, not before.

Exercise 1.1

Write a well-structured English sentence with invalid tokens in it. Then write another

sentence with all valid tokens but with invalid structure.

When you read a sentence in English or a statement in a formal language, you have

to ﬁgure out what the structure of the sentence is (although in a natural language

you do this subconsciously). This process is called parsing.

欢迎加入非盈利Python编程学习交流QQ群783462347，群里免费提供500+本Python书籍！

剩余263页未读，继续阅读

weixin_38744153

粉丝: 346
资源: 2万+

Python编程：像计算机科学家一样思考

How_To_Think_Like_A_Computer_Scientist-Learning_With_Python

How to Think Like a Computer Scientist: Learning with Python Documentation Release 2nd Edition

Python for Software Design How to Think Like a Computer Scientist.pdf

how to think like a computer scientist- learning with python 3

python learn role

think python 下载

现在我有一个数据表，里面有30种职业，都是文字型的变量，帮我用Python 把这30种职业进行嵌入式编码，并给出结果，你自己虚构数据

现在我有一个数据表，里面有30种职业，都是文字型的变量，我现在准备用它进行建模，帮我用Python 把这30种职业进行嵌入式编码，并给出结果，你自己虚构数据

根据文件“scientist.txt”的内容，用文本为参数的方法绘制中文词云，设置用前60个高频词生成词云，背景色为白色，用“ball.jpg”作背景图片或自选背景图片。

python spacy 一段文字岗位名称抽取

Give a brief introduction to a novel including the following aspects: - genre - characters - plot - setting - theme

三台虚拟机ssh免密登录

多线程实现科学家就餐

写一个python程序。利用pycrfsuite库。训练crf模型，给一个bio序列贴上另一个bio序列的标签，然后利用此训练好的模型，给新的bio序列贴上新的bio标签

python dataframe保存为xlsx

the scientist and engineer's guide to digital signal processing.pdf

面试筛选到面试录用的功能怎么实现用代码

csdn接入chat gpt了吗

important numpy

最新资源