🎓 A1Learner
🔍
0 of 47 lessons completed

PowerShell CSV Data

CSV is a text format that stores rows of data with values split by commas. The first row names each column, and each later row holds one record.

Write a file and read it back

Export-Csv writes the rows to a file. Import-Csv reads them back as objects.

$people = @(
    [PSCustomObject]@{ Name = "Ana"; Age = 31 }
    [PSCustomObject]@{ Name = "Ben"; Age = 28 }
)
$path = Join-Path $PSScriptRoot "people.csv"
$people | Export-Csv -Path $path -NoTypeInformation
$back = Import-Csv -Path $path
$back[0].Name
$back[1].Name

Convert CSV text without a file

ConvertTo-Csv makes the same text in memory. ConvertFrom-Csv turns that text back into objects.

$people = @(
    [PSCustomObject]@{ Name = "Ana"; Age = 31 }
    [PSCustomObject]@{ Name = "Ben"; Age = 28 }
)
$text = $people | ConvertTo-Csv -NoTypeInformation
$text
$fromCsv = $text | ConvertFrom-Csv
$fromCsv[1].Name

Check a round trip by joining names

Join the names before and after the round trip. If both joined strings match, nothing was lost.

$people = @(
    [PSCustomObject]@{ Name = "Ana"; Age = 31 }
    [PSCustomObject]@{ Name = "Ben"; Age = 28 }
)
$path = Join-Path $PSScriptRoot "people.csv"
$people | Export-Csv -Path $path -NoTypeInformation
$back = Import-Csv -Path $path
$original = ($people | Select-Object -ExpandProperty Name) -join ", "
$roundTrip = ($back | Select-Object -ExpandProperty Name) -join ", "
$original
$roundTrip
$original -eq $roundTrip

Example

$people = @(
    [PSCustomObject]@{ Name = "Ana"; Age = 31 }
    [PSCustomObject]@{ Name = "Ben"; Age = 28 }
    [PSCustomObject]@{ Name = "Eli"; Age = 24 }
)
$path = Join-Path $PSScriptRoot "people.csv"
$people | Export-Csv -Path $path -NoTypeInformation
$back = Import-Csv -Path $path
($back | Select-Object -ExpandProperty Name) -join ", "
$original = ($people | Select-Object -ExpandProperty Name) -join ", "
$roundTrip = ($back | Select-Object -ExpandProperty Name) -join ", "
$original -eq $roundTrip

Key points

  • Export-Csv: Use Export-Csv to write objects to a CSV file, one row per object.
  • NoTypeInformation: The -NoTypeInformation switch leaves out the extra type line at the top of the file.
  • Import-Csv: Use Import-Csv to read a CSV file back into objects.
  • Property reads: Each object read back has one property per column, read with a dot.
  • In-memory forms: ConvertTo-Csv and ConvertFrom-Csv do the same work on text, with no file involved.

In this example, three rows are written to a file and read back. The joined names show the rows came back, and the comparison confirms the names match the originals exactly.

Note

Values read back from CSV are text, even when they looked like numbers before.

Try it Yourself

Edit the code, then press Run.

Running is simulated

Exercise

Which cmdlet reads a CSV file back into objects?