Comparison between two strings is not working

Question

I've got a problem with a comparison between two Versions.

PS C:\Windows\system32> $soft.DisplayVersion -lt "124.0"
False

I expect it to return True because the value of $soft.DisplayVersion is :

PS C:\Windows\system32> $soft.DisplayVersion
95.0

Object Type :

PS C:\Windows\system32> $soft.DisplayVersion.GetType()

IsPublic IsSerial Name                                     BaseType                                                                                                                                                            
-------- -------- ----                                     --------                                                                                                                                                            
True     True     String  

I also tried this:

PS C:\Windows\system32> $soft.DisplayVersion -lt 124.0
False

I don't know if it helps but $soft.DisplayVersion comes from this:

Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\* | Where-Object DisplayName -match "Mozilla Firefox" 

Let me know if you need extra information to understand my problem.

Answer 1

The registry key of origin and the comparison operand imply that you're dealing with version numbers.

To meaningfully compare version numbers based on their string representations, cast them to [version]:

[version] $soft.DisplayVersion -lt [version] '124.0'

Note:

• For brevity, you could omit the RHS [version] cast, because the LHS cast would implicitly coerce the RHS to [version] too. However, using it on both sides can help conceptual clarity.

• For a [version] cast to succeed, the input string must have at least 2 components (e.g. [version] '124.0' and at most 4 (e.g, [version] '124.0.1.2'), and each component must be a positive decimal integer (including 0).

• [version] is not capable of parsing semantic version numbers, however, which are limited to 3 components and may contain non-numeric suffixes (e.g., 7.5.0-preview.2).

  • Use [semver] to parse semantic versions; however, that type is available in PowerShell (Core) 7 only.

  • Unlike with [version], a single component is sufficient in the input string of a [semver] cast; e.g.,
    [semver] '124' works to create version 124.0.0.

---

As for what you tried:

• $soft.DisplayVersion -lt "124.0" and $soft.DisplayVersion -lt 124.0 are equivalent, and neither works as intended:

  • Because the LHS operand is a string, -lt coerces the RHS operand to a string too, and then performs lexical comparison, which is not what you want: '95.0' -lt '124.0' '95.0' -lt 124.0 are both false, because the character '9' is greater than the character '1'.

• [decimal]$soft.DisplayVersion -lt 124.0 (from your own answer) works only for version-number strings up to two components; e.g. [decimal] '95.0.1' would break.

Answer 2

I will used this syntax :

[version]$soft.DisplayVersion -lt [version]"124.0.1"


PS C:\Windows\system32> [version]$soft.DisplayVersion

Major  Minor  Build  Revision
-----  -----  -----  --------
124    0      1      -1      



PS C:\Windows\system32> 

Thanks @lit and @mklement0 this is perfect :)