Oddity in Powershell operators

Tags:

powershell

Here's the problem. To simplify a complex script, I have built a small menu.

Quit
User1
User2
...

The list of users is dynamic (up to a maximum) defined as $counter. This dynamic list is composed of names from previous runs of the script (via being dotsourced). In addition to these users, I let the client type in names not defined in the subset, sort of a "Other" field.

PS PS:\> $counter
10
PS PS:\> $answer
8
PS PS:\> $answer -lt $counter
False

Why?? Why oh Why? Here's what I found..

PS PS:\> $counter -is [int32]
True
PS PS:\> $answer -is [int32]
False

"8" does not equal 8. In fact, "8" is greater than 10. I've tried to use the scriptcenter's isNumeric function, but had mixed results with it. The problem happens that I put the entire segment into a function.

Function IsNumeric ([string] $a) {
[reflection.assembly]::LoadWithPartialName("'Microsoft.VisualBasic")
$b = [Microsoft.VisualBasic.Information]::isnumeric($a)
Return $b
}

Problem is that my function was returning an array, containing both the vbScript load statement and $true or $false. I found that by moving:

[reflection.assembly]::LoadWithPartialName("'Microsoft.VisualBasic")

outside my function, it now functions correctly. Whew!

Comments

Submitted by Jason Archer (not verified) on Mon, 2009-11-09 11:15.

That isn't an oddity, just

That isn't an oddity, just need to be careful with types. Since you probably used Read-Host, it returns a string. So cast the result as an integer:

[int]$answer = Read-Host ...

Something that needs to be watched for in dynamically typed languages.

Submitted by ericwoodford on Thu, 2009-11-12 12:00.

Yes, but, I wanted both!

Ideally I wanted my script to accept both number values from a menu I displayed or a string of characters (user's mailbox info).

If I dot-source the code, the variable complains the second run. Hmm, give me an idea on why that error keeps coming up.

Thanks,

en Passant