1.0.2 Background Information - IP
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>> Hello everyone and welcome back to
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the new intro to Python course on Siberia on-demand.
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If you're here, that means you saw the intro video,
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liked what you saw and decided to come back for more.
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That is absolutely spectacular news for us,
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and particularly for me.
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I'm very excited to have you here and
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>> I'm very excited to be teaching you this course.
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>> Today, we're going to start with Lesson 0.
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Lesson 0 is called Lesson 0 because in programming,
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your very first lesson, we will always index from 0.
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That is key to a lot of
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different parts of computer science.
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It's going to be very important to
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know because if you mess that up,
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you can actually break some pretty astonishing things.
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Lesson 0 soapbox temporarily
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over Lesson 0 is called some background.
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Over the course of Lesson 0,
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we're going to learn about the history of Python.
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We're going to learn about the philosophy of Python.
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I know that sounds a weird thing to say right now,
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the philosophy of Python.
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But it actually does have
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an underlying underpinning philosophy
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and we're going to talk about that,
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and why it's important.
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Then we're going to understand the core functionality
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of Python, what it does,
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how it does, what it does,
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and why it works that way.
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A very, very brief history of Python.
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It was developed in 1991,
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it was released in 1991.
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It was developed by Guido Van Rossum
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over the year preceding that.
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Guido Van Rossum was quoted saying that he decided he
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needed a project to keep him busy over the holidays,
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and decided he would create a language to be
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a spiritual successor to ABC,
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which turned into Python.
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He actually did this as
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a side project just over the holidays,
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I have gone to some extreme lengths to
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avoid spending time with my family and in-laws before.
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But I have to say I've never
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invented a programming language.
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That's pretty impressive.
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Version 3 of the most current major version
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of Python was actually released in 2008,
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just over 10 years ago.
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Version 2 is actually still in use in some places,
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we're going to talk about a little bit here.
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Version 2 of Python is used primarily in
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organizations that are resistant
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to change for some reason.
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A lot of times it's the federal government,
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sometimes it's big corporations that just have
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a huge code base that they can't switch over.
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There a lot of causes,
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but fundamentally, it's been
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more than 10 years now since Version 3 was released.
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Version 2 was intended to be end-of-life,
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I think a couple of years ago now,
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and is now that got pushed back to
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2020 for fear of messing up people's systems.
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But it will be end of life around 2020.
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It's really, really important that we use Version 3,
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and then we upgrade to Version 3
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because it really is an upgrade.
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Version 3 is qualitatively superior to Version 2,
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for a whole host of reasons.
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Not least that it actually
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better follows a lot of programming paradigms.
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All of that said,
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the reason I'm bringing it up and
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the reason why I addressed it here is
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because all of the code in this class and all of
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the programming experience you will gain here,
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will be in Python 3,
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we will not use Python 2 at any point.
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If you're in an organization that needs you to
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learn Python 2, not the place.
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By not the place, I mean not the organization.
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Don't write Python 2 code it's not a good idea.
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This slide is extremely information
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dense and I just want to say,
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don't try and read all of the material on this slide.
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That's not at all what it's for,
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and I don't want you trying to do that.
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However, I wanted to put it up here and it'll be
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in your supplemental material as
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well in a more readable format because there are
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a few specific lines that I want you to see,
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and I want to address here.
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Explicit is better than implicit.
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Simple is better than complex.
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Complex is better than complicated.
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Those three aphorisms are self satisfying statements.
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Statements that are self-contained and they
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are a single point of truth or belief.
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Those are all contained in the Zen of Python,
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which is PEP 20, which is actually
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a Python guiding document.
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The idea here is that this list
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of concept or this list of ideas,
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governs all of the development of Python,
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and governs all of the concepts that are built
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into the language that make it function
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the way it does today.
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The three that I addressed,
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explicit is better than implicit,
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simple is better than complex,
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and complex is better than complicated,
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are not only the first three lines,
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but they're my three favorite lines.
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They're really important to this course,
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and really any Python programming you'll do.
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Because of the fact that when you're writing code,
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more rather when you're working with code,
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more often you're going to be
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>> reading it than writing it.
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>> You only write a program once,
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maybe a couple of times if you're
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rebuilding it for some reason.
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But you're going to write
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the code once and then you're going to have to
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read it over and over again to sustain it,
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to fix it, to supplement it,
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other people are going to come along and have to
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read your code and try and understand what it does.
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Python was intended to be a
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>> very human-readable language.
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>> When you're writing Python
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code you should keep that in mind.
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Sometimes you can't avoid having complex code,
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but if you have to write complex code,
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it's better to write a couple of lines of
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complex code and then write
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a bunch of comments to explain it,
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than it is to have some behemoth monster,
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thousands and thousands of lines of
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Python code that don't make any sense.
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Simple as always, the best option.
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But if you can't be simple,
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at least don't be complicated.
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Or again, this is a very information dense slide.
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It's very small, it's hard to read.
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This is mostly just here to illustrate.
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It's not here for you to try and read through.
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The Zen of Python PEP 20 will
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be in your supplemental materials.
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The design of Python, how
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it actually works under the hood.
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We're not going to get super,
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super technical with this because this
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is an intro level course.
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But essentially what matters here for people
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who've worked with programming languages before,
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we've had to do like memory management
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in C or garbage clean up.
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All of that is handled under the hood in Python,
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you don't have to use malloc,
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you don't have to associate virtual memory,
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all of that is handled for you.
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Python is a relatively secure language
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in terms of memory safety,
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because of the fact that it takes it out of users hands.
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It's a relatively memory-safe language,
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and it's going to do most of that hard work for you.
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Python functions on what's called a REPL.
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There are people who would call that a REPL loop.
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Those are the same monsters who say things
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like ATM machine and pin number.
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REPL stands for read execute print loop.
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It's not a REPL loop, it's
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just a REPL period or a REP loop if you must say loop.
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I understand that this is not
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important and it doesn't matter.
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But it does matter to me because I'm
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a pedantic person and this is important to me.
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[LAUGHTER] But more seriously,
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REPL read execute print is the way that
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the Python implementation interprets your code,
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the way the interpreter interprets
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your code, that's what I was looking for.
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It will read a line of code.
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It will gain the context of that line if it needs
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other lines for more information
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or if it needs other data,
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it will then execute that turn into machine code,
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give it to your system that actually run,
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and then it will print the results.
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Now, that's in the interpreter,
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if you're writing a Python script,
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it will not print every line.
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A lot of time
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in script it's only going to print when you tell it to.
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On the interpreter side,
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if you're assigning the result to a variable,
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it's not going to print to the screen,
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because it's being piped to that variable.
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But the concept still stands.
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It reads, it executes,
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and it outputs that information
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either to print or to some other storage location.
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There are coding conventions in the Python and we will to
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some extent address them during the syntax lesson.
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However, we are not going to
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spend a whole bunch of time on them
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because this is actually
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another quote from Guido Van Rossum.
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A foolish consistency is the hob goblin of little minds,
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which is to say that it is more important to write
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clear readable code that
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matches the style of whatever project you're on,
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than it is to match every single detail
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of the Python coding convention.
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It is more important that your code be easy
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to use and easy to understand,
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than that you use exactly the right cases for everything.
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The coding conventions are useful and I like to
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follow them and you should follow
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them, and feel free to read them.
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You can see that they're on the slide
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>> as a link and supplemental materials.
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>> We'll also include that link,
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but they're not laws, they're guidelines.
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A knowledge check,
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what does REPL stands for?
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I'll give you just a couple of seconds.
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Read execute print loop.
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I don't put loop there because I want to
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specify it is a read execute print,
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and that is being done in a loop.
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Which PEP covers the Zen of Python?
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PEP 20. Which PEP covers the Python conventions?
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I actually don't know that I said it out loud,
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but that is going to be PEP 8.
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Like I said, it's not actually
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terribly, terribly important.
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It's useful and it's good to know and you
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should learn it and you should look up
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>> PEP 8 and read it.
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>> But it's much more important that you write
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functional, easy to read code.
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That's all there is for Lesson 0.
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When you come back to Lesson 1,
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we're going to discuss programming basics, logic.
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We're going to really dig into some
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Boolean logics, some truth tables.
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We're going to have a great time over the course
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of this lesson as
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our knowledge check suggested
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we learned about the history of Python,
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we learned about the fundamental workings of it.
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Of course, we learned that it is much more
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important to be easy to read than it is to be pretty.
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Thank you all very much and I look
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forward to seeing you in the next video.
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