Swift Tutorial II

Ok so in the first tutorial we covered let, which is the keyword for defining constants.

let thisBeAConstant = 3.141

Now we are going to cover variables, which use the var keyword like so:

var thisVariable = time

Notice 2 things about Swift:

1) We don’t use ; at the end of a line.  That’s just weird 🙂

2) We don’t have to specify the type.  The type is inferred by whatever value you pass in, so:

var someString = “this is a string”

var someInteger = 5

So Swift is kinda smart.  Now let’s meet some old friends “Hao jiu bu juan”

ARRAYS

var energies = [“solar”“wind”“fossil”, “this is a mixed array”, 39]

var energies:String[] = [“solar”“wind”“this is a string array”]

And of course we can perform some basic operations such as:

READ

var item1 = energies[0]   // “solar”

INSERT

energies.insert(“hydro”, atIndex: 2)

MODIFY

energies[3] = “geothermal”

APPEND

energies.append(“nuclear”)

or

energies += “nuclear”

COMBINE

energies += [“biomass”“hamster”]

COUNT

var lengthofArray = energies.count

LOGIC

var arrayIsEmpty = energies.isEmpty

REMOVE

energies.removeAtIndex(3)
energies.removeLast()
energies.removeAll(keepCapacity: true)
MUTATE
If we used let energies, then our array is immutable, vs if we used var energies which means its mutable.
Easy as pie.
DICTIONARIES

var energies = [

    “Solar”“Thermal”,
    “Photovoltaic” : “Grid”,
    “Nuclear” : “Dangerous”
]
Here our keys are Solar, Photovoltaic & Nuclear.  These keys can be strings or numeric values such as integers.
Once again we can:
READ
let cheapestSolarEnergy = energies[“Solar”]
COUNT
var energiesCount = energies.count
MODIFY
energies[“Solar”] = “PV”
REMOVE
energies[“Nuclear”] = nil;
INSERT
energies[“Geo”] = “Thermal”
and of course the value of a key can be an array or another dictionary:

var typesOfEnergy =

[
    platforms[“Solar”]: [“Thermal”“PV”“GridTied”],
    platforms[“Wind”]: [“Autonomous”“GridTied”],
    platforms[“Nuclear”] : [“Fusion”“Fission”,“Meltdown”]
]
and we would read it:
var type1 = typesOfEnergy[“Solar”][0]
See you next time! 🙂
Advertisements

One thought on “Swift Tutorial II

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s