init commit

Author: Sentdex

10. basic Functions intro.py

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+'''
+Hello everyone and welcome to another python 3 basics video. In this video we
+will be discussing the basics of a function.
+
+The idea of a function is to assign a set of code, and possibly variables,
+known as parameters, to a single bit of text. You can think of it a lot like
+why you choose to write and save a program, rather than writing out the
+entire program every time you want to execute it.
+'''
+
+# To begin a function, the keyword 'def' is used to notify
+# python of the impending function definition, which is what def
+# stands for.
+
+# from there, you type out the name you want to call your function.
+# it is important to choose a unique name, and also one that wont conflict
+# with any other functions you might be using. For example, you wouldn't
+# want to go calling your function print. 
+
+
+# so here we've called our function example. After the name of the function,
+# you specify any parameters of that function within the parenthesis
+# parameters act as variables within the function, they are not necessary
+# to create a function, so first let's just do this without any parameters. 
+
+def example():
+    # functions just run whatever code is encased with them.
+    print('this code will run')
+    z = 3 + 9
+    print(z)
+
+# now if we just run this, we see nothing happens. We have to actually call
+# this function to execute, because all we've done so far is just define the
+# function and what it does. To run it, you can either type out the function in
+# the console like so:
+
+# or you can add it to the actual script itself:
+
+example()
+

11. Function Parameters.py

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+'''
+Welcome to another python 3 basics video, in this video we will carryon with
+functions. In the last video you were shown a very basic function, without
+any parameters
+
+In this video, lets include a parameter, and give this function more...
+functionality. 
+'''
+
+
+# changed name to simple math, to better describe our intentions
+'''
+Now we've specified 2 parameters for our function, calling them num1
+and num2, for number 1 and number 2.
+
+Now, we carry on writing our function, where we can specify what we
+desire to do with num1 and num2.
+
+in our case, we want to do simple addition.
+'''
+def simple_addition(num1,num2):
+    answer = num1 + num2
+    print('num1 is', num1)
+    # so here the answer variable will be filled with whatever
+    # num 1 plus num 2 is.
+    print(answer)
+    # then at the end, we want to print out the answer to the client
+
+
+'''
+so now we run this, and when we want to do some simple_addition...
+'''
+
+simple_addition(5,3)
+# here we will do 5 + 3, for an answer of 8
+
+'''
+There is no limit to the amount of variables you can have. The only thing
+you will want to look out for at this point is the order of the variables,
+
+as well as the quantity.
+
+You can protect yourself from order by doing the following in your calling:
+'''
+
+simple_addition(num1=3,num2=5)
+# or more clearly #
+simple_addition(num2=3,num1=5)
+
+# in this case, if you are clear in your specification, it does not matter
+# the order. Most people, however, do not write out the variables like that,
+# they just maintain the order.
+
+
+#finally, it is important to use the proper quantity of variables.
+
+# will not work, too many vars
+simple_addition(3,5,6)
+
+# will not work, too few vars
+simple_addition(3)
+
+
+
+
+'''
+That's it for this video, in the next video I willbe covering default variable
+assignments. 
+
+'''
+
+
+
+
+
+

12. Function Parameter Defaults.py

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+'''
+Hello again and welcome to another python 3 basics video. In this video we
+will be covering default function parameters
+'''
+
+# so normally, you write a function like so:
+def simple(num1,num2):
+    pass
+
+# What you can do, however is:
+
+def simple(num1, num2=5):
+    # what this does is specify a "default parameter" just in case
+    # one is not specified.
+    # this is useful so all parameters dont need to be called
+    # every single time. Generally, this is used for modules.
+    # an example would be a module that makes windows for users.
+    pass
+
+
+# so here, the user must specifiy width and height, but a font of times
+# new roman, for example, is the default so they dont have to say that
+# every single time.
+
+def basic_window(width,height,font='TNR'):
+    # let us just print out everything
+    print(width,height,font)
+
+
+
+# now, when we call basic_window, we can break a rule we established
+# earlier:
+
+# see, only two parameters, when we require 3
+basic_window(350,500)
+
+# we can do this because there is a default if font is not specified. Should
+# a user wish to specify however, they can do
+
+basic_window(350,500,font='courier')
+
+# here, it is just important that you place any parameters with default values
+# at the very end, to avoid trouble when calling the function down the road. 

13. Global and Local Vars.py

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+'''
+Welcome to another python 3 basics video, in this video we're going to now
+discuss the concept of global and local variables.
+
+When users begin using functions, they can quickly become confused when it comes
+to global and local variables... getting a the dreaded variable is not defined
+even when they clearly see that it is... or so they think.
+
+These terms of global and local
+correspond to a variable's reach within a script or program.
+
+A global variable is one that can be accessed anywhere
+
+A local variable is the opposite, it can only be accessed within its frame.
+
+The difference is that global variables can be accessed locally, but not modified
+locally  inherently.
+
+A local variable cannot be accessed globally, inherently.
+Now, dont worry about committing
+that to memory right now, I think it makes a lot more sense when you just
+see and do it, so let's do that. 
+
+'''
+# this variable has no parent function, but is actually NOT a global variable.
+# it just so happens that it is committed to memory before the function is called
+# so we are able to iterate, or call it out, but we cannot do much else.
+
+x = 6
+
+def example():
+    # z, however, is a local variable.  
+    z = 5
+    # this works
+    print(z)
+    
+example()
+# this does not, which often confuses people, because z has been defined
+# and successfully even was called... the problem is that it is a local
+# variable only, and you are attempting to access it globally.
+
+print(z)
+
+# next up is an example that i've seen cause even more trouble, and that's
+# the attempt to play with a global variable locally. The reason why this
+# is so troubling is because you can access it... you just cannot play
+# with it, and this often frustrates people for a while.
+
+
+x = 6
+
+def example2():
+    # works
+    print(x)
+    print(x+5)
+
+    # but then what happens when we go to modify:
+    x+=6
+
+    # so there we attempted to take the x var and add 6 to it... but now
+    # we are told that we cannot, as we're referencing the variable before
+    # its assignment.
+
+'''
+So now you know the rules, what can we do about it?
+'''
+x = 6
+
+def example3():
+    # what we do here is defined x as a global variable. 
+    global x
+    # now we can:
+    print(x)
+    x+=5
+    print(x)
+
+
+
+
+'''
+So that is all for global and local, though I will show 1 last thing.
+
+Sometimes you want a sort of global variable as a starting point, but
+you do not actually wish to modify the "global" variable outside of the
+functions themselves. You can just do the following:
+'''
+
+def example4():
+    globx = x
+    # now we can:
+    print(globx)
+    globx+=5
+    print(globx)
+
+
+# and that's it!
+
+# hopefully that will help some of you from pulling your hair out for 30 minutes
+# trying to figure out what the heck is going on to reality. This is something
+# that snagged me pretty good when i was starting out. 

14. modules.py

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+'''
+At this point, you've got all the basics necessary to start employing modules.
+
+We still have to teach classes, among a few other necessary basics, but now
+would be a good time to talk about modules.
+
+
+IF you are using linux, installing python modules is incredibly stupid easy.
+For programming, linux is just lovely when it comes to installing packages
+for just about whatever. I believe mac allows similar treatment, though I've
+not done it myself.
+
+When I was first starting out with python, installing modules was one of the
+most difficult things, for a few reasons.
+
+mainly, with windows, there are quite a few methods for installation of modules.
+you've got pip install setuptools, download and click'n'drag, or setup.py
+
+At the time of starting python, a large part of my troubles was that I didn't
+actually understand the process of getting a module, and this is obviously very
+frustrating.
+
+Python is going to look in a few places for modules.
+
+That's going to be site-packages and the script's directory for the most part.
+There are some other places you can use, but let's leave them out of it. Knowing
+this allows you yourself to make your own modules, in the form of just a script
+if you want, putting that in the same directory as your main script, and then
+using import to bring it on board, you can also place multiple scripts in a dir
+and use that. Once you begin to familiarize yourself with this, and understand
+how and why things work, it will help you a lot.
+
+Enough on that though, let's install stuff. 
+
+So I will show linux installation first, because it takes about 10 seconds to
+show
+
+
+
+
+now for python, the accepted method these days is setup.py
+
+So when you download a python module,
+
+http://www.pyqtgraph.org/
+
+
+
+... now finally, you can use downloaders, here is a large stash
+of easy to use python installers for windows:
+http://www.lfd.uci.edu/~gohlke/pythonlibs/
+
+'''
+
+
+
+
+

…imple print function and string rules.py …imple print function and string rules.py1. simple print function and string rules.py renamed to 2. simple print function and string rules.py 1. simple print function and string rules.py renamed to 2. simple print function and string rules.py

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+1+3
+4*4
+5-2
+5/2
+
+
+
+#exponents
+4**4
+
+4.5*2
+
+#Integers whole numbers
+
+

3. simple maths.py

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+'''
+Hello and welcome to my variables tutorial video. In this video I will teach
+you about variables, which you will quickly find yourself using extremely
+frequently. 
+
+Variables act as a placeholder for whatever you place in them, and, can be
+changed... so they are... you guessed it... VARIABLE!
+'''
+
+
+exampleVar = 55
+print(exampleVar)
+
+#cannotDo = Hey!
+
+canDo = 'Hey!'
+print(canDo)
+
+canContainOperations = 5/4
+print(canContainOperations) 
+
+#canEvenContainFunctions = # but more on that later....

4. variables.py

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+
+
+condition = 1
+
+while condition < 10:
+    print(condition)
+    condition += 1
+
+
+condition = '2'
+
+while condition > 5:
+    print 'test'
+
+# Another favorite of many people... the infinite loop #
+
+while True:
+    print('doing stuff!!')
+
+
+
+# control+c to break script!
+
+
+
+
+
+