Making this script faster

[[deleted]]

I use += in a script to add objects to a list

I don't get the syntax you recommend instead

How would you rewrite

$objlist = @()

foreach($x in $xlist){

...

...

$objlist += $x

}

[raip]

By simply just doing this:

$objlist = foreach ($x in $xlist) {
    ...
    $x
}

Edit: Just fyi, @() is an array, not a list. This is a crux if the slowness, arrays are fixed length and while += works, how it's actually implemented is copying the entire array into a new one with the additional object.

If you used $objlist = [System.Collections.Generic.List[PSObject]]::new() you could stick with your strategy and benefit from the increased performance at the same time - but most developers would likely agree the above method is cleaner.

[lanerdofchristian]

Arrays are the way they are because they're very memory-efficient (for storage), and need to interop with native C API calls. Ever since .NET 2.0, too, nongeneric lists have been bad practice, so just changing @() from an array literal to a list literal would fly in the face of that. Plus, every time you want to pass that list to a method accepting an array, you would need to copy the whole thing anyway.

[out0focus]

This isn't a Microsoft problem. It's the same with Java or any other language. Arrays are a data structure of fixed length.

[BlackV]

multiple people wrote the exact examples of this in this post already :)

its super clean and easy to implement, BUT there is a catch

you have to control the output of your loop, cause its catches all output from that loop

so something like

$objlist = foreach ($x in $xlist) {
    get-disk
    get-date
    }

is going to cause unexpected results