Storing information

Computers remember

Have you ever forgotten a distant relative's name or a friend's birthday? Well, computers don't forget these things when they're told to remember them.

OK computer:
remember Joe as my name
display my name

//Output Below

Joe

The North .. err .. the computer remembers until we tell it to hold on to a different name.

Psst: these instructions are a little oversimplified, of course, but we'll get to actual computer-speak in no time.

Variables

To remember things, computers use variables, a concept that's a lot like boxes with labels. Variables, too, have a label and content.

OK computer:
remember 1970/1/1 as my birthday
display my birthday

//Output Below

1970/1/1

Great! Just like you'd label a box my birthday, it makes sense to call a variable my birthday, right?

Labels

In computer-speak, labels have to be single letters or single words, which disqualifies my birthday.

Can you think of a valid label?

  • my_birthday
  • 1/1
  • your birthday
  • 1970

Sweet it's the first! Labels don't have to be real words and can include numbers, as long as they don't start with them. Also, it's smart to use meaningful labels.

Tracking information

Now, why would we use variables when we could also use the information they carry?

OK computer:
remember "Walter White" as my_name
display my_name

//Output Below

Walter White

Well, because variables can change the values they represent as the program runs. That's why we can use variables to keep track of things.

Different kinds of information

There are different kinds, or types, of information. Most importantly, there are words and numbers.

Which two statements would you say make sense?

OK computer:
  • add "White" to my_name
  • add 1 year to my_birthday
  • subtract 1 year from my_name

It wouldn’t make sense to subtract a year from your name, would it?

Numbers

There are different kinds of numbers as well. Among others, whole numbers and floating-point numbers.

OK computer:
divide 10 by 3
display the result
divide 10 by 1
display the result

//Output Below

3.3333333333
10

In practice, floating-point numbers often occur when we divide whole numbers.

Using numbers

Also, numbers are great for arithmetic.

OK computer:
remember 1 as my_number
add 42 to my_number
multiply my_number by 3
display the result

//Output Below

129

Boom! Even if we were mathematicians, it'd be hard to beat the arithmetic accuracy and speed of computers.

Strings

Words, which are also called strings, have quotation marks and can't be used for arithmetic. They're still pretty great, though.

Have a guess: What's the computer going to display?

OK computer:
remember my_name as "Walter"
add "White" to my_name
display my_name
  • WalterWhite

Yup, the strings are combined without a space. As spaces are also strings, we've got to add them if we want to see them.

Lists

As we've seen, variables are kind of like boxes for values. What if we want to store more values, though?

Well, there are boxes with space for multiple values: lists.

OK computer:
create a list
add "cereal" to the list
add "milk" to the list
display the list

//Output Below

cereal, milk

See that? Lists are a great way to store multiple values; especially, if they're of the same kind.

Author

Laryea

Web Developer