Combine two CSV files in powershell without changing the order of columns - powershell

Question

I have "a.csv" and "b.csv" . I tried to merge them with below commands
cd c:/users/mine/test
Get-Content a.csv, b.csv | Select-Object -Unique | Set-Content -Encoding ASCII joined.csv
But I got Output file like b.csv added by end of the row of a.csv. I wanted add by end of the column of a.csv then b.csv columns should begin
Vm Resource SID
mnvb vclkn vxjcb
vjc.v vnxc,m bvkxncb
Vm 123 456 789
mnvb apple banana orange
vjc.v lemon onion tomato
My expected output should be like below. Without changing the order
Vm Resource SID 123 456 789
mnvb vclkn vxjcb apple banana orange
vjc.v vnxc,m bvkxncb lemon onion tomato

Answer 1

From here, there are two ways to do it -
Join-Object custom function by RamblingCookieMonster. This is short and sweet. After you import the function in your current PoSh environment, you can use the below command to get your desired result -
Join-Object -Left $a -Right $b -LeftJoinProperty vm -RightJoinProperty vm | Export-Csv Joined.csv -NTI
The accepted answer from mklement which would work for you as below -
# Read the 2 CSV files into collections of custom objects.
# Note: This reads the entire files into memory.
$doc1 = Import-Csv a.csv
$doc2 = Import-Csv b.csv
$outFile = 'Joined.csv'
# Determine the column (property) names that are unique to document 2.
$doc2OnlyColNames = (
Compare-Object $doc1[0].psobject.properties.name $doc2[0].psobject.properties.name |
Where-Object SideIndicator -eq '=>'
).InputObject
# Initialize an ordered hashtable that will be used to temporarily store
# each document 2 row's unique values as key-value pairs, so that they
# can be appended as properties to each document-1 row.
$htUniqueRowD2Props = [ordered] #{}
# Process the corresponding rows one by one, construct a merged output object
# for each, and export the merged objects to a new CSV file.
$i = 0
$(foreach($rowD1 in $doc1) {
# Get the corresponding row from document 2.
$rowD2 = $doc2[$i++]
# Extract the values from the unique document-2 columns and store them in the ordered
# hashtable.
foreach($pname in $doc2OnlyColNames) { $htUniqueRowD2Props.$pname = $rowD2.$pname }
# Add the properties represented by the hashtable entries to the
# document-1 row at hand and output the augmented object (-PassThru).
$rowD1 | Add-Member -NotePropertyMembers $htUniqueRowD2Props -PassThru
}) | Export-Csv -NoTypeInformation -Encoding Utf8 $outFile