Performing Comparisons Inside Arrays

# what does this code do? Let's find out!
$selection = @($preference, "Default" -ne $null)[0]

# This creates an array of 2 values. Arrays are good at holding multiple values
@('value1','Value2')

# To verify that this is of the array type, Run
@('value1','value2') -is [array]

# We can use an index number to select which value we want out of the array
# We put the index number inside []
# [0] returns the first  value in the array, which is value1.
@('value1','Value2')[0]

# [1] returns the second value in the array (counting starts at 0), which is value2.
@('value1','value2','value3')[1]

# to get the last value in the array, we specify [-1]
@('value1','value2','value3')[1]

# Comparison operators compare things and then tell us if the comparison was true or false.
# Is 'Toby' the same string as 'Scranton Strangler'?
'Toby' -eq 'Scranton Strangler'
# darn, we almost had him.

'Pinocchio' -eq 'Real Boy'
# ouch, poor guy

# We can also determine if things are Null or not
$null -eq 'Michael'

5 -lt 6

# We haven't defined the NonExistentVariable yet, so it doesn't exist yet.
$null -eq $NonExistentVariable

# Let's have an array and put a comparison operator in it.
# This allows us to sort of filter
@(1,2,3 -GT 1)

@('','notBlank' -notlike '')

# Create an array without any null values.
@($NonExistentVariable, 'string' -ne $null)

# We need to select a new office color. We would like to use the color in $preference.
# if $preference is null, then we will return 'CorporateGrayscale'
$newOfficeColor = @($preference, "CorporateGrayscale" -ne $null)[0]
# We have an array with a comparison. This effectively filters out any null values.
# we then select the [0] value, which will either be $preference or "corporateGrayscal"
# I hope that someone defined $preference 0_O

# This is how I traditionally would have handled something like this
if ($preference){
    $newOfficeColor = $preference
}
else {
    $newOfficeColor = "CorporateGrayscale"
}


# This is the actual code that was updated
$mimeType = [System.Web.MimeMapping]::GetMimeMapping($File)
$ContentType = @($mimeType, "application/octet-stream" -ne $null)[0]

# Old long code
$mimeType = [System.Web.MimeMapping]::GetMimeMapping($File)
if ($mimeType) {
    $ContentType = $mimeType
}
else {
    $ContentType = "application/octet-stream"
}