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So to get started, let's talk about converting and formatting data values.

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This is a common task that when building PowerShell

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scripts that you'll have to do,

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which will be converting a number to something else or a text value to

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something else or maybe going a little bit deeper into,

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for example, .NET typed objects.

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So first off, what type of variables are there?

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Well, there's what's referred to as loosely typed.

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These are when a value is assigned to effectively an undefined type of variable.

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Now as you've seen so far in the previous modules,

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we just create a variable called $variable and assign a value.

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That would be a loosely typed variable.

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The second option is a strongly typed variable.

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This is where you are assigning the type to that variable.

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So, for example, this variable will be a integer,

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or this will be a string, and the only type of data that it can contain is that.

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We can use variables to store data.

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We can store all types of values within PowerShell variables.

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A variable is just a unit of memory in which those values actually get stored.

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We then declare those variables by just using the dollar sign before the name.

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Variable names aren't necessarily case‑sensitive,

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and they can include spaces and special characters.

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But I will advise you to try and keep them without spaces

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and special characters and just create them with dollar and

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a name that makes sense to you.

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Now there are different variable types available to us.

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The first is user‑created variables.

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So we just go in and create them,

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and they're available to us in the context of the

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PowerShell script that we're executing.

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We then have what's referred to as automatic variables,

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and we'll talk a little bit more about this.

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And then, of course, we have preference variables.

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Preference variables are really around some of the configuration around the

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PowerShell script itself or the execution and things like that.

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So first off, we have user‑created variables.

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These are created and maintained by you as the user.

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The variables created within the command line exist

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only in the context of that window.

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So if I open up a PowerShell console and create $variable equals 10,

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then I can't close that window and reopen it and

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expect to find that same value there.

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The automatic variables store the state of PowerShell.

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Now PowerShell create these variables and changes their values as required,

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and you can execute this.

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So, for example, we can use a $ps, for example,

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and let's say environment or env, so psenvironment.

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It would be an automatic variable that we can access.

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Then, of course, we have preference variables.

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So they are variables that store user preferences for PowerShell.

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These variables, once again,

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get created by PowerShell and get populated with default values.

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However, they could be changed.

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So how do we create user variables?

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Well, it's as simple as doing this, dollar,

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the name, equals, and set it to a value.

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So you can see I have three variables here.

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One is set to a comma‑separated set of numbers.

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One is a string value.

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One is a string data value.

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Now don't get confused here.

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Just because it's in a date format does not make that variable date type.

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It's just a string.

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Now if I wanted to create a typed variable,

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I can do this a little bit differently.

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This is where we define what that variable can contain.

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So you'll see my variable 1 is now going to contain an integer.

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So in square brackets, I type Int,

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which is the strong type of what I wish to add in there.

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The same would go for the DateTime.

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Now there are common variable data types that we can

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utilize outside of int and datetime.

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We have boolean, so the yes/no value, a date time.

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We also have a PowerShell object, and we'll talk about those a little bit later.

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We then have a script block, which is obviously other executed PowerShell,

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a string value, which is obviously the most common,

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and then, of course, an array of objects.

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Now once we start grabbing data and populating it into variables,

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one of the most common things we have to do is to convert or

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what's referred to as cast those data values.

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Casting is about converting one object type to another so

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that we can utilize it into something else.

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Not all objects can be cast,

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so you can't just randomly say I want this type of

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value to be cast to something else.

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You have to be careful.

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So converting objects from one to another,

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often you would mitigate some of these issues by just defining the

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variables with the right types to begin with.

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So let's look at how we would cast variables and values.

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So I have two variables here.

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Variable 1 is the number 1.

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Variable 2 is clearly a date, 01/01/2021.

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If I want to convert a string variable to an integer,

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I'm going to prefix the variable with Int as the strong type.

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If I want to convert the string variable to a date,

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I need to put DateTime in front of that specific variable.

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If I want to convert a false value to an integer,

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so a false or a true, I can simply put int before it,

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and it will then give it its either 0 or 1 value.

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When a value is cast to a particular datatype, it's a one‑time change.

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So it doesn't have to happen all the time.

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It's just I converted it and changed it at that point.

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When a variable is cast to a particular datatype,

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it will stay that way unless it's updated again.

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So just think that through.

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If we go back one slide, when a value is cast to that

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datatype, it's a single transaction.

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When a variable is cast, it will stay that way.

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So if you define a variable as an integer,

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it will always stay an integer unless you update.

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Now what we do have is we have an operator called the ‑as operator.

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This will allow you to cast things to a specific thing. Now it also

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serves the purpose for being able to test a conversion. So you can use

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that as operator to say, well, if I convert this to that,

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will it work?

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You can also define the type after the variable by using the as command.

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And then, of course,

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the big thing here to worry about is that it can have unexpected results.

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It may not work the way that you're expecting because,

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as I mentioned before,

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you cannot cast everything into anything, and the as is such

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an easy way of doing it that it doesn't necessarily work the

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way that you're expecting.

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So what's the syntax look like?

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Well,

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let's go back and have the same two variables, variable1, string

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value number, variable2, date string value.

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If I want to cast it as an integer, I can simply say

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variable1 ‑as using the operator Int.

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If I want to do the date, I can do the same process and say as date.

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And if I wanted to do the same thing as I did before,

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so casting the false value to an integer, I can do false as an

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integer. So a couple of different ways of doing it.

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It really depends how you want to write the PowerShell script. I like to use

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the defined variables just because it kind of makes more sense that way that

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you control the input to get what you want.

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But if you're kind of ad hoc, on the fly,

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you may not want to have input or there's no input that

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comes in, this may be the output of something else, then

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you can use that as operator.

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Now we also have what's called the f operator.

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This is used to format a string expression.

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So instead of us casting objects, we can format the values into something else.

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This supports complex formatting. And you can begin the statement

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with the selected format, so what you would like that to be in. So

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let's look at how we format the data values.

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So what does this look like in PowerShell?

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So I have two variables here.

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You can see that one is a 123 point something,

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and then the other variable is just a standard number.

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It actually looks like a phone number.

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If I want to display only the three decimal places,

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you can see that we can use this kind of syntax.

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Now remember,

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we said we put this at the beginning of the variable. So you'll

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see that in quotes, in brackets, it will be 0: and then 0 being

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the actual value that's coming in.

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And then you've got n3, which will tell it that I only

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want to show the three decimal places, and then the ‑f is telling it to format.

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If I want to convert variable2 into a phone number with spaces,

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same principle again.

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You do this before the variable,

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and it will be squirrely brackets, 0 is the value coming in,

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and then the colon is the format on the right. And you can see, I'm

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doing 3‑3‑4. If I want to display the year only from the current

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date, I can do this and say 0: year, year,

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year year, which will then, I'm using not a variable.

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I'm using a command called Get‑Date,

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which will get me the current date of today, but only

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return back the year. Now of course,

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dates are the most common one that you would see where

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you would be formatting as in month, month ‑d, d for day, ‑year,

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year, year.

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So that's a common use case, but it works for numbers, as well as regular text values.