Think Python - Denison University

viChapter 0. PrefaceIn 2003 I started teaching at Olin College and I got to teach Python for the first time. The contrastwith Java was striking. Students struggled less, learned more, worked on more interesting projects,and generally had alot morefun.Over the last five years I have continued to develop the book, correcting errors, improving some oftheexamplesandaddingmaterial,especiallyexercises. In2008Istartedworkonamajorrevision—at the same time, I was contacted by an editor at Cambridge University Press who was interested inpublishing the next edition. Good timing!The resultisthis book, now withthe lessgrandiose titleThink Python. Some of thechanges are:• I added a section about debugging at the end of each chapter. These sections present generaltechniques forfinding and avoiding bugs, and warnings about Python pitfalls.• I removed the material in the last few chapters about the implementation of lists and trees. Istilllove those topics, but Ithought they were incongruent withthe restof thebook.• Iaddedmoreexercises,rangingfromshorttestsofunderstandingtoafewsubstantialprojects.• I added a series of case studies—longer examples with exercises, solutions, and discussion.SomeofthemarebasedonSwampy,asuiteofPythonprogramsIwroteforuseinmyclasses.Swampy, code examples, and somesolutions are available fromthinkpython.com.• I expanded thediscussion ofprogram development plans and basic design patterns.• The use of Python is more idiomatic. The book is still about programming, not Python, butnow Ithink thebook gets moreleverage from thelanguage.Ihopeyouenjoyworkingwiththisbook,andthatithelpsyoulearntoprogramandthink,atleastalittlebit,likeacomputer scientist.AllenB. DowneyNeedham MAAllen Downey is an Associate Professor of Computer Science at the Franklin W. Olin College ofEngineering.AcknowledgementsFirstandmostimportantly,IthankJeffElkner,whotranslatedmyJavabookintoPython,whichgotthisproject startedand introduced me towhat has turned out tobe myfavoritelanguage.I also thank Chris Meyers, who contributed several sections to How to Think Like a ComputerScientist.And I thank the Free Software Foundation for developing the GNU Free Documentation License,which helped make my collaboration withJeffand Chris possible.Ialsothank theeditors at Lulu who worked on How toThink Like aComputer Scientist.Ithankallthestudentswhoworkedwithearlierversionsofthisbookandallthecontributors(listedbelow) who sent incorrections and suggestions.AndIthankmywife,Lisa,forherworkonthisbook,andGreenTeaPress,andeverythingelse,too.