Variable

A variable is a placeholder for a value, like `x` in math: `var x=3;`. We can assign a value to a variable and read the current value:

```var x = 1;
println(x);
x = 3;
println(x);```
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`println` is a simple function to print on the screen the given value. You can see that the values printed are 1 and then 3.

Numbers

One obvious kind of data

`1+2`
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Strings

Aside from numbers, a very common type of data is the String which is something between double quotes, like a name `"John"`.

`"John" + "Doe"`
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```var name="John";
println(name);
name="Mary";
println(name);```
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Arrays

So, we can think of a single variable as a "block" of memory where we can store something. An array is a couple of such blocks, tied together... here's an array with 3 numbers in it: `[5,2,6]`.

Here's an array:

`var x=[1,2,3];`
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```var x=[1,2,3];
println(x)
println(x)
println(x)```
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```var x=[1,2,3];
x.length```
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```var x=[1,2,3];
for(i=0; i<x.length; i++) {
println(x[i])
}```
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