Seite - 96 - in Programming for Computations – Python - A Gentle Introduction to Numerical Simulations with Python 3.6, Band Second Edition

96 4 FunctionsandtheWritingofCode will be regarded as the final version (in general, however, programs are typically changedandimprovedagainandagain,makingithardtoreach the“final”version!). DevelopingaComputationalPlan To write a program, you need to plan what that program should do, and a good plan requires a thorough understanding of the addressed problem. One fundamentally important thing with the step-wise strategy, is that it invites you to think through your computational problem very carefully: What bits and pieces, or “sub-problems”, make up the whole task? Should the “sub- problems” be solved in any particular order, i.e., do parts of the problem depend on results from other parts? What is the best way to compute each of the “sub-problems”? This kind of thinking, which combines favorably with discussions among students/colleagues, often pays off in terms of a much deeper understanding of the problemat hand.Goodsolutionsoften requiresuchanunderstanding. CompoundStatements Theconstructionsmet in thischapter,and thepreviouschapter,arecharacter- ized by a grouping of statements that generally span several lines (although it is possible to write simpler cases on a single line, when statements are separated with a semi-colon). Such constructions are often referred to as compoundstatements, havingheaders (endingwitha colon)andbodies (with indentedstatements).a Interactive handling of compound statements is straight forward. For example,afor loopmaybewritten (andexecuted) like In [1]: for i in [1, 2, 3]: # write header, press enter ...: print(i) # indent comes automatically ...: # press only enter, i.e., finished 1 2 3 When the header has been typed in and we press enter, we are automatically given the indent on the next line. We can then proceed directly by writing print(i) and press enter again. We then want to finish our loop, which is understoodwhenwesimplypressenter,writingnothingelse. a https://docs.python.org/3/reference/compound_stmts.html.