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diff --git a/advanced-features-functions/script.rst b/advanced-features-functions/script.rst deleted file mode 100644 index a420721..0000000 --- a/advanced-features-functions/script.rst +++ /dev/null @@ -1,277 +0,0 @@ -.. Objectives -.. ---------- - -.. At the end of this tutorial, you will be able to - -.. 1. Assign default values to arguments, when defining functions -.. 2. Define and call functions with keyword arguments. -.. 3. Also, you will get a glimpse of the plethora of functions -.. available, in Python standard library and the scientific computing -.. libraries. - - -.. Prerequisites -.. ------------- - -.. 1. getting started with ipython -.. #. getting started with functions - -.. Author : Puneeth - Internal Reviewer : Anoop Jacob Thomas<anoop@fossee.in> - External Reviewer : - Language Reviewer : Bhanukiran - Checklist OK? : <put date stamp here, if OK> [2010-10-05] - -Script ------- - -{{{ Show the slide containing title }}} - -Welcome to the tutorial on advanced feature of functions. - -{{{ Show the outline slide }}} - -In this tutorial we shall be looking at specifying default arguments -to functions when defining them and calling functions using keyword -arguments. We shall also, look at some of the built-in functions -available in the standard library of Python and the scientific -computing libraries. - -{{{ switch to terminal }}} - -We have an ``ipython`` terminal open, which we shall be using through -out this session. - -Let's use the ``round`` function as an example to understand what a -default value of an argument means. Let's type the following -expressions in the terminal. - -:: - - round(2.484) - - round(2.484, 2) - -Both the first expression and the second are calls to the ``round`` -function, but the first calls it with only one argument and the second -calls it with two arguments. By observing the output, we can guess -that the first one is equivalent to call with the second argument -being 0. 0 is the default value of the argument. - -.. #[[Anoop: It will be good if we show ``round??`` and tell them the - optional argument ndigits, or it could be given as an - exercise(solved) asking them to find the name of the argument in - the function round]] - -{{{ show a slide with examples of functions showing default values }}} - -.. #[[Anoop: I think the slide is not there]] - -:: - - s.strip() # strips on spaces. - s.strip('@') # strips the string of '@' symbols. - - plot(x, y) # plots with x vs. y using default line style. - plot(x, y, 'o') # plots x vs. y with circle markers. - - linspace(0, 2*pi, 100) # returns 100 points between 0 and 2pi - linspace(0, 2*pi) # returns 50 points between 0 and 2pi - -.. #[punch: all above content goes on to a slide] - -{{{ switch back to ipython }}} - -Let's now define a simple function that uses default arguments. We -define a simple function that prints a welcome message to a person, -given a greeting and his/her name. - -:: - - def welcome(greet, name="World"): - print greet, name - -Let us first call the function with two arguments, one for ``greet`` -and other for ``name``. - -:: - - welcome("Hi", "Guido") - -We get the expected welcome message, "Hi Guido". - -Now let us call the function with just one argument "Hello". -:: - - welcome("Hello") - -"Hello" is treated as the ``greet`` and we get "Hello World" as -the output. "World" is the default value for the argument ``name``. - -Following is an (are) exercise(s) that you must do. - -{{{ switch to next slide, containing problem statement of - question 1 }}} - -%%1%% Redefine the function ``welcome``, by interchanging it's -arguments. Place the ``name`` argument with it's default value of -"World" before the ``greet`` argument. - -Please, pause the video here. Do the exercise and then continue. - -{{{ switch to next slide, containing the solution to problem 1 }}} - -:: - - def welcome(name="World", greet): - print greet, name - -We get an error that reads ``SyntaxError: non-default argument follows -default argument``. When defining a function all the argument with -default values should come at the end. - -.. #[[Anoop: In the slide, "when defining a function all the default - arguments must be defined at the end" has to be emphasized"]] - -Following is an exercise that you must do. - -{{{ switch to next slide, containing the problem statement of - question 2 }}} - -%%2%% See the definition of linspace using ``?`` and observe how all -the arguments with default values are towards the end. - -Please, pause the video here. Do the exercise and then continue. - -{{{ switch to next slide, containing solution to problem 2 }}} - -:: - - linspace? - -Following is an exercise that you must do. - -{{{ switch to next slide, problem statement }}} - -%%3%% Redefine the function ``welcome`` with a default value of -"Hello" to the ``greet`` argument. Then, call the function without any -arguments. - -Please, pause the video here. Do the exercise and then continue. - -{{{ switch to next slide, solution }}} - -:: - - def welcome(greet="Hello", name="World"): - print greet, name - - - welcome() - - -Let us now learn what keyword arguments or named arguments are. We -shall refer to them as keyword arguments, henceforth. - -{{{ show a slide with examples using keyword arguments. }}} - -.. #[[Anoop: slide is missing]] - -:: - - legend(['sin(2y)'], loc = 'center') - - plot(y, sin(y), 'g', linewidth = 2) - - annotate('local max', xy = (1.5, 1)) - - pie(science.values(), labels = science.keys()) - -When you are calling functions in Python, you don't need to remember -the order in which to pass the arguments. Instead, you can use the -name of the argument to pass it a value. This slide shows a few -function calls that use keyword arguments. ``loc``, ``linewidth``, -``xy`` and ``labels`` are being called with keyword arguments. - -{{{ switch to ipython terminal }}} - -Let us try and understand this better using the ``welcome`` function -that we have been using all along. Let us call it in different ways -and observe the output to see how keyword arguments work. - -:: - - welcome() - - welcome("Hello", "James") - - welcome("Hi", name="Guido") - -When no keyword is specified, the arguments are allotted based on -their position. So, "Hi" is the value of the argument ``greet`` and -name is passed the value "Guido". -:: - - welcome(name="Guido", greet="Hey! ") - -When keyword arguments are used, the arguments can be called in any -order. - -:: - - welcome(name="Guido", "Hey") - -This call returns an error that reads, ``non keyword arg after keyword -arg``. Python expects all the keyword to be present towards the end. - -That brings us to the end of what we wanted to learn about ``keyword`` -arguments. - -{{{ switch to a slide showing variety of functions with uses }}} - -.. #[[Anoop: slide missing]] - -Before defining a function of your own, make sure that you check the -standard library, for a similar function. Python is popularly called a -"Batteries included" language, for the huge library that comes along -with it. - -:: - - Math functions - abs, sin, .... - -.. #[punch: Need to decide, exactly what to put here. Reviewer comments -.. welcome.] - -{{{ switch to slide showing classes of functions in pylab, scipy }}} - -.. #[[Anoop: slide missing]] - -Apart from the standard library there are other libraries like ``pylab``, -``scipy``, etc which have a huge collection of functions for scientific -purposes. -:: - - pylab - plot, bar, contour, boxplot, errorbar, log, polar, quiver, semilog - - scipy (modules) - fftpack, stats, linalg, ndimage, signal, optimize, integrate - -{{{ Show summary slide }}} - -.. #[[Anoop: add range of functions available in python standard - library]] - -That brings us to the end of this tutorial. In this tutorial we have -learnt how to use functions with default values and keyword -arguments. We also looked at the range of functions available in the -Python standard library and the Scientific Computing related -packages. - -{{{ Show the "sponsored by FOSSEE" slide }}} - -This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India - -Hope you have enjoyed and found it useful. -Thank you! |