This helps users with small displays and makes it possible to have severalĬode files side-by-side on larger displays. Wrap lines so that they don’t exceed 79 characters. Nesting depth) and large indentation (easier to read). Every Pythonĭeveloper should read it at some point here are the most important pointsĤ spaces are a good compromise between small indentation (allows greater It promotes a very readable and eye-pleasing coding style. Making it easy for others to read your code is always a good idea, and adoptingĪ nice coding style helps tremendously for that.įor Python, PEP 8 has emerged as the style guide that most projects adhere to Most languages can be written (or moreĬoncise, formatted) in different styles some are more readable than others. Now that you are about to write longer, more complex pieces of Python, it is a Here is an example of a multi-line docstring: Equivalence of whitespace should be tested after expansion Indented less should not occur, but if they occur all their leading whitespace Then stripped from the start of all lines of the string. Generally adjacent to the string’s opening quotes so its indentation is notĪpparent in the string literal.) Whitespace “equivalent” to this indentation is The first non-blank lineĪfter the first line of the string determines the amount of indentation for This is done using the following convention. Python, so tools that process documentation have to strip indentation ifĭesired. The Python parser does not strip indentation from multi-line string literals in Theįollowing lines should be one or more paragraphs describing the object’s calling If there are more lines in the documentation string, the second line should beīlank, visually separating the summary from the rest of the description. Since these are available by other means (except if the name happens to be a For brevity, it should not explicitly state the object’s name or type, The first line should always be a short, concise summary of the object’s There are emerging conventions about the content and formatting of documentation The method append() shown in the example is defined for list objects itĪdds a new element at the end of the list. Object types and methods, using classes, see Classes) Obj.methodname, where obj is some object (this may be an expression),Īnd methodname is the name of a method that is defined by the object’s type.ĭifferent types define different methods. A method is a function that ‘belongs’ to an object and is named The statement result.append(a) calls a method of the list object Return without an expression argument returns None. The return statement returns with a value from a function. This example, as usual, demonstrates some new Python features: while a > f100 = fib2 ( 100 ) # call it > f100 # write the result """Return a list containing the Fibonacci series up to n.""". > def fib2 ( n ): # return Fibonacci series up to n. This value can be assigned to another name whichĬan then also be used as a function. The value of the function name has a type that is recognized by the interpreterĪs a user-defined function. Local symbol table is created for that call.Ī function definition introduces the function name in the current symbol table. 1 When a function calls another function, a new Passed using call by value (where the value is always an object reference, Symbol table of the called function when it is called thus, arguments are The actual parameters (arguments) to a function call are introduced in the local Within a function (unless named in a global statement), although they Thus, global variables cannot be directly assigned a value More precisely, all variable assignments in aįunction store the value in the local symbol table whereas variable referencesįirst look in the local symbol table, then in the local symbol tables ofĮnclosing functions, then in the global symbol table, and finally in the table The execution of a function introduces a new symbol table used for the local Practice to include docstrings in code that you write, so make a habit of it. There are tools which use docstrings to automatically produce online or printedĭocumentation, or to let the user interactively browse through code it’s good (More about docstrings can be found in the section Documentation Strings.) This string literal is the function’s documentation string, or docstring. The first statement of the function body can optionally be a string literal The statements that form the body of the function start at the next line, and It must beįollowed by the function name and the parenthesized list of formal parameters. The keyword def introduces a function definition. while a > # Now call the function we just defined. def fib ( n ): # write Fibonacci series up to n.
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