The JavaScript array method .join() will combine all elements of an array into a single string. Syntax var array = ["Lorem", "Ipsum", "Dolor", "Sit"]; var str = array.join([separator]); Parameters separator Optional. Specifies the string to use to separate each element of the original array. More on forum.freecodecamp.org

I would try a forEach loop with either push for each element or splice if it push isn't working. More on reddit.com

$HRfile | Where-Object { $_.HRempID -eq $user.EmployeeID } Whenever I see this pattern in a loop, I always suggest creating an index. Hastables can make this easy: $HRFileEmployeeIDIndex = @{} foreach ($Item in $HRfile) { $HRFileEmployeeIDIndex[$Item.HRempID] = $Item } Now you can directly lookup the Item in $HRfile with that value: foreach( $UserItem in $UserList ) { $row = $HRFileEmployeeIDIndex[$user.EmployeeID] $user.CostCenter = $row.HRcostCenterCode } This requires the value to be unique. If it's not unique I would run it through Group-Object first, to create an array for each value. Then index the results of Group-Object. More on reddit.com

If it's a consuming iterator of Strings, you can do:

string_iter.collect::<Vec<String>>().join(", ")

Which I benchmarked against itertools::join and got these results:

test consume_collect_join   ... bench:      63,260 ns/iter (+/- 18,295)
test consume_itertools_join ... bench:      82,640 ns/iter (+/- 30,842)

When you have a borrowing iterator of Strings you can do:

string_ref_iter
    .map(|s| &**s)
    .collect::<Vec<&str>>()
    .join(", ")

Again that seems faster than the itertools equivalent:

test borrow_collect_join    ... bench:      24,071 ns/iter (+/- 11,873)
test borrow_itertools_join  ... bench:      41,002 ns/iter (+/- 6,126)

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