Question:
Problem Statement: The Count and Keys properties can get overloaded by a hash value and not return their expected values.
My Powershell Code is this:
|
1 2 3 4 5 6 7 8 |
$hash = @{} $hash.one = "Number 1" $hash.two = "Number 2" "Count is [{0}]" -f $hash.Count $hash.Count = "Count's Hash Value" "Count is now [{0}]" -f $hash.Count |
My Output is this:
|
1 2 3 |
Count is [2] Count is now [Count's Hash Value] |
The Count Property gets overloaded! This issues could cause users some very hard to diagnose bugs. Had me confused for a good while. Same issue applies to “Keys” or in fact any Property.
Do you have any thoughts on best practice to avoid this one? Maybe a different System.Collection? or prefixing all Keys with a character such as:
|
1 2 |
$key = ":" + $key |
However, its not very elegant. Even now that I know the issue, I suspect I will forget and make the same mistake again.
I personally think it is a problem with the Powershell Language Definition. The . notation (as in $hash.MyKey) should not be allowed for retrieving hash values, only for retrieving Property values. Just a thought. 🙂
Thanks for your help.
Answer:
You can directly call property get accessor instead of accessing property or use Select-Object -ExpandProperty:
|
1 2 3 |
@{Count=123}.get_Count() @{Count=123}|Select-Object -ExpandProperty Count # does not work on PowerShell Core |
In PowerShell v3+ you could also use
PSBase or PSObject automatic property:|
1 2 3 |
@{Count=123;PSBase=$null}.PSBase.Count @{Count=123;PSObject=$null}.PSObject.Properties['Count'].Value |