powershell convert array of hastables into csv - powershell

Question

Have done googling but have not found suitable answer
I have
$a = #(
#{"name"="a"; "value"="1"},
#{"name"="b"; "value"="2"}
)
Foreach($x in $a){
$obj = New-object psobject
Foreach($key in $x.keys) {
$obj ¦ add-member -membertype NoteProperty -name $key -value $x[$key]
}
$obj ¦ export-cvs test.csv
}
I get only last line in cab. I want all the lines

Answer 1

It's truth that Export-Csv won't append (< v3), but I do not think ConvertTo-Csv will solve the problem... In the end you will get file with headers repeated for every object in your array. I would suggest one of two things:
move Export-Csv outside foreach {} (need to put it in subexpression though, because it won't be possible to pipe it by default)
use Foreach-Object instead and get same results
I would also suggest to use New-Object PSObject -Property parameter instead of adding members later: because you use hashtable as a base you are half way there, see attached code samples:
# Using $( foreach ($x in $a) {} ) | Export-Csv
$(Foreach($x in $a){
New-object psobject -Property $x
}) | Export-Csv test.csv
# Using $a | Foreach-Object {} | Export-Csv
$a | ForEach-Object {
New-Object PSObject -Property $_
} | Export-Csv test.csv

Answer 2

You're overwriting the csv file each time. Try using convertTo-CSV each time (instead of export-csv) and appending that to a file.

Answer 3

2022 update
You always need to use the -append parameter if you are iterating through a collection
using powershell 7.2 and later you don`t need to parse the hashtable again, it matches the repeating properties and writes to csv.
so this will work automatically
$hashtable=#()
$hashtable += $pscustomobject
$hashtable | export-csv