-Contains operator not working powershell - powershell

Question

All I'm trying to do is to see if the user input $month is in the array $months. But it's not liking something. Help?
Write-host "The script is to collect from the user High Tempature and Low Tempature for a day in degrees F."
$months = #("January", "February","March","April","May","June","July","August","September","October","November","December")
$finished = $false
while ($finished -eq $false){
$month = read-host "Enter the month";
if ($months -Contains $month)
{
write-host "Invalid entry"
$finished = $false
}
else
{
$finished = $true
}
}

Answer 1

You test logic is just not the good one, just reverse youy test or reverse your actions:
Write-host "The script is to collect from the user High Tempature and Low Tempature for a day in degrees F."
$months = #("January", "February","March","April","May","June","July","August","September","October","November","December")
$finished = $false
while ($finished -eq $false){
$month = read-host "Enter the month";
if ($months -Contains $month)
{
$finished = $true
}
else
{
write-host "Invalid entry"
$finished = $false
}
}

Answer 2

Instead of using -Contains you should just run a RegEx match using the -Match operator. Or, as you are currently testing for a negative result, use -notmatch instead. You can use your existing code, just modify it a little by joining your months with a pipe character. Like:
Write-host "The script is to collect from the user High Tempature and Low Tempature for a day in degrees F."
$months = #("January", "February","March","April","May","June","July","August","September","October","November","December")
$finished = $false
while ($finished -eq $false){
$month = read-host "Enter the month";
if ($month -notmatch ($months -join "|"))
{
write-host "Invalid entry"
$finished = $false
}
else
{
$finished = $true
}
}
Better yet, let's get rid of the If/Else and shorten this. Move the Join to where we define $Months, and then ask for a month and if it isn't a match ask for it again until it is with a While.
$months = #("January", "February","March","April","May","June","July","August","September","October","November","December") -join '|'
$month = read-host "Enter the month"
While($month -notmatch $months){
"Invalid Entry"
$month = read-host "Enter the month"
}