Prepend folder name to paths in an array - windows

Question

I'm looking to prepend a folder name to the start of an array of (relative) paths using a foreach statement, but it's not making any changes to the array (no errors either)
Note: This is more for educational purposes than functional as I have it working using a for loop which I've commented out, but I'm interested in learning how the foreach statement works
$myFiles = #(
"blah1\blah2\file1.txt"
"blah3\blah4\file2.txt"
"blah5\blah6\file3.txt"
)
$checkoutFolder = "folder1"
#for ($h = 0; $h -lt $myFiles.Length; $h++) {
#$myFiles[$h] = $checkoutFolder + "\" + $myFiles[$h]
#}
foreach ($path in $myFiles) {
$path = $checkoutFolder + "\" + $path
}
$myFiles
I also tried using a buffer variable e.g.
$buffer = $checkoutFolder + "\" + $path
$path = $buffer
But same result i.e.
OUTPUT:
blah1\blah2\file1.txt
blah3\blah4\file2.txt
blah5\blah6\file3.txt

Answer 1

I could think of two ways:
Create new array with modified data of old array
$myFiles = #(
"blah1\blah2\file1.txt"
"blah3\blah4\file2.txt"
"blah5\blah6\file3.txt"
)
$checkoutFolder = "folder1"
#Create new array $myFilesnew
$myFilesnew = #()
#For each line in in old array
foreach ($file in $myFiles)
{
#Create new row from modied row $file of $myFiles array
$row = $checkoutFolder+"\"+$file
#Add row $row to a new array $myFilesnew
$myFilesnew+=$row
}
$myFilesnew
Modify each row of existing array:
$myFiles = #(
"blah1\blah2\file1.txt"
"blah3\blah4\file2.txt"
"blah5\blah6\file3.txt"
)
$checkoutFolder = "folder1"
$i=0
while($i-lt $myFiles.Count)
{
#Get $i row $myFiles[$i] from aray, perform insert of modified data, write data back to $myFiles[$i] row of the array
$myfiles[$i]=$myFiles[$i].Insert(0,$checkoutFolder+"\");
#Add +1 to $i
$i++
}
$myFiles

Answer 2

Better start using the Join-Path cmdlet to avoid creating paths with backslashes omitted or doubled.
Something like this would do it:
$checkoutFolder = "folder1"
$myFiles = "blah1\blah2\file1.txt", "blah3\blah4\file2.txt", "blah5\blah6\file3.txt" | ForEach-Object {
Join-Path -Path $checkoutFolder -ChildPath $_
}
$myFiles
output:
folder1\blah1\blah2\file1.txt
folder1\blah3\blah4\file2.txt
folder1\blah5\blah6\file3.txt

Answer 3

You can replace the regex beginning of each string with the folder name. This is a useful idiom for generating computernames too.
'blah1\blah2\file1.txt','blah3\blah4\file2.txt','blah5\blah6\file3.txt' -replace '^','folder1\'
folder1\blah1\blah2\file1.txt
folder1\blah3\blah4\file2.txt
folder1\blah5\blah6\file3.txt