one of Python for Everybody. I'm Charles

Severance i'm your instructor and i

welcome you to this class. The basic goal

of this class is to teach everybody how

to program regardless of your background.

You don't have to be a math whiz. You

don't have to be a computer expert. No

matter how old you are or what your

background is we want to teach you how

to program. So welcome to this course.

Welcome to chapter one.

So the first thing to understand is that

the purpose to learn to program is

because computers want to do things for

us they are built and created and

designed and their hardware is set up so

that they basically asked us what do you

want to do next if you grab your phone

your phone sort of does nothing until

you tell it what to do with weights for

you and is just waiting for you and all

the hardware computer technology around

you is generally waiting for you and we

can use this for useful things we could

play video games we could have it help

navigate for our car someday we might

even have self-driving cars and its

really in a sense in my mind silly if

you spend your whole life not really

understanding this technology and and I

think it's important that we learn to

tell these computers what to do rather

than just let them increasingly control

our lives and so as we'll see computers

aren't very smart on their own we humans

are the ones that in view them with

knowledge and what we need to learn to

speak their language it is much easier

for us to learn to speak their language

than it is for them to learn to speak

our language although with these

cellphones we're starting to see little

bits where they can begin to understand

but you would be amazed at the 40 or 50

years that it takes has taken us to

understand a hundred to build programs

to begin to understand so I'm bringing

you into something where you are going

to learn the ways of programming

in the let ways of the computer because

it's easier to teach you how to program

is to teach this how to work in your

world even though ultimately the goal is

to get this to to do work for you

so part of what i'm trying to do is move

you from a user perspective where you

just look at the computer as something

that someone else has constructed and

you are the user of to the point where

you construct new things now the first

kinds of things that you're going to

construct are actually things to solve

your own problems and it's a very

popular now to work on data and python

is an excellent programming language for

datum data mining and data analysis and

that's a lot of what we're going to do

in this course although really it's a

gateway to all kinds of things like you

know artificial intelligence or gaming

navigation or mobile applications or

entertainment all kinds of things but

first we have to learn to program we

have to move from using the computer as

a tool to using the tools within the

computer that allow us to change how the

computer sees the world so there's a

couple of reasons that you might want to

be a programmer some of you are looking

to improve your career to be paid to

work on program and I've been a paid

program for most of my life and I like

it it's a good job you don't have to

stand in the mud you don't have to lift

things you have to use your brain and

i'll just say that it is been nice for

my career to not be exposed to the

elements but to be able to work often

wherever I want but that's actually our

secondary goal our first goal is to get

you to write programs that solve

problems that you have to solve maybe

you have a job as an accountant or a

lawyer or something else and maybe you

run across some data maybe there's some

system that logs your time and it's not

quite giving the report that you want to

give and so you say could I just grabbed

the log data myself and and write a

program to do some analysis to say

what's the average this versus that or

the average of some other thing right

and so that's the basic idea that you'll

you'll initially use computers to serve

your own ends

that makes it a lot easier to write

programs because you don't have to worry

about

you know a million users using your

software you if it works for you then

we're happy and so it takes a little

more training to write software for

other people are for thousands and

thousands of other people and so part of

what i want to do is I want to change

your perspective you know you look at

this from the outside and you see it

from the outside and you click on things

i want to turn this around and I want

you to be the person inside this looking

out at the world and as a programmer we

are making things inside these computers

for the world and so we want to pull you

into being part of this we want you

inside this are thinking inside this and

what you learn is that if you're inside

this computer and you are taking your

instructions to build programs to be

used by the human almost dropped that

the human outside the computer you have

things that you need to take advantage

of there's things like the central

processing unit the memory of this

system the network connection of this

system that the disk drive or permanent

storage on this system and as a

programmer you are kind of mediating

between all those internal resources

that this has that are not very smart

but highly powerful and mediating with

what that user wants right and so we

take the end user and we programmers we

serve the end-user but the computer

serves us so together between us and all

the computers resources we can serve the

needs of the end user and we do this by

writing code or programming ok and what

is that well

programming is a sequence of

instructions where we are giving

instructions the resources inside the

computer in a way to accomplish the

goals of the end user and remember

sometimes we are our own end-user it's

not just it's not just you know the

you're not always doing a start-up

you're not always writing a mobile

gaming system sometimes you're writing

something for yourself but that's okay

so sometimes you're writing something to

solve a problem you're like crafting

your you're doing something you could do

by hand or manually and you're you're

making some clever little 2500 line

program and you're putting that in other

times like when I work on the

open-source learning management system

sakai it is my creativity I'm I've got

an idea and I want to share it with a

million users and so I write my code to

for an external audience and so code is

that sequence of instructions that the

computer itself doesn't know how to

handle roster out but i can write code

that will handle roster out by looking

at the data that's inside this computer

inside this application and so if you

think about programs we have programs

for computers and programs for humans

and a number of years ago now i'm

started sooner or later this will be me

showing my age

this is an example of the macarena and

the macarena is a song that effectively

is a sequence of instructions

you put your left hand out you put your

right hand out you put on the shoulder

you wiggle wiggle wiggle and you spin

around and you do things and this this

is a program for people and so I want

you to take a quick look at this and see

if you can find anything wrong with this

particular program to look really

closely

so i'll show you it's got some

typographical errors in it and we as

humans are really good at reading or

hearing typographical errors and

correcting them automatically and

instantly and but computers are not

computers are extremely literal if it

saw this ham instead of hand it would

think what's a ham and why am I going to

hit someone in the back of the head with

a ham and why would I take my left hand

and hit somebody that's you know these

are all bad things but the computer is

going to take us very literally

and so we have to be really precise and

and the computer just doesn't know the

difference between what we mean and what

we say so we have to be very precise and

this is one of the great frustrations

that people have when they first start

using computers and so we have to get

this right we have to get these little

bits of text exactly the way they are

computers will blow up with syntax

errors and there seemed to to make quite

a fuss when you make the tiniest of

errors but you'll get used to that I

mean that's because not because you're

bad or you're less than awesome

it just means the computers can't

compensate when you make small mistakes

and so you've got to get used to the

fact that the computer is sort of

intellectually not as strong as you

and so it gets confused really easy even

though when it gets confused

it says seemingly mean things to you so

you'll get used to that

ok so the first thing i want to do is I

want to throw up some text and I want

you to while this text is up i want you

to count the number of each word in this

text and tell me what the most common

word is in this text

ok so here we go

ok so I I kind of made that hard on you

on purpose by moving around and

distracting you and confusing you

but even if it's it's not moving at all

it's a little bit you know tricky to do

you probably stare at a couple of times

your brain is going back and forth and

back and forth and so let's text

analysis is one of the great things that

computers are very very good at and some

of the things that you know if they can

translate text and that's because they

looked at a lot of information so

looking at text is actually something

computers are really good at and so if