PowerShell ConvertFrom-Csv
last modified February 15, 2025
In this article, we will cover the ConvertFrom-Csv cmdlet in
PowerShell. This cmdlet converts comma-separated value (CSV) data into objects.
CSV basics
CSV is a simple file format used to store tabular data. Each line represents
a record, with fields separated by commas. PowerShell can work with CSV data
through various cmdlets. The ConvertFrom-Csv cmdlet is essential
for processing CSV strings or files.
Basic ConvertFrom-Csv usage
The simplest way to use ConvertFrom-Csv is with a CSV string.
The first row should contain headers (property names). Each subsequent row
becomes an object with those properties. The output is a collection of objects.
$csvData = @" Name,Age,Occupation John,32,Engineer Sarah,28,Designer Michael,45,Manager "@ $objects = $csvData | ConvertFrom-Csv $objects
This command converts a CSV string into objects. Each object has Name, Age, and Occupation properties. The output shows the objects in table format.
Working with custom delimiters
By default, ConvertFrom-Csv uses commas as delimiters. You can
specify different delimiters with the -Delimiter parameter. This is useful
for files using tabs, semicolons, or other separators. The delimiter must
match the actual separator in your data.
$csvData = @" Name;Age;Occupation John;32;Engineer Sarah;28;Designer Michael;45;Manager "@ $objects = $csvData | ConvertFrom-Csv -Delimiter ';' $objects
This command processes CSV data with semicolon delimiters. The output is identical to comma-delimited data but parsed correctly. The -Delimiter parameter ensures proper field separation.
Converting CSV from a file
You can combine Get-Content with ConvertFrom-Csv
to process CSV files. First read the file content, then convert it to objects.
This approach is common when working with external data files. The file must
have proper CSV formatting.
$fileContent = Get-Content -Path "C:\data\employees.csv" $objects = $fileContent | ConvertFrom-Csv $objects | Format-Table -AutoSize
This command reads a CSV file and converts it to objects. The Format-Table cmdlet ensures clean output. Adjust the file path to match your system.
Working with headers
If your CSV lacks headers, you can specify them with the -Header parameter. Provide an array of column names to use as property names. This is useful for files without header rows. The headers will be applied to all subsequent rows.
$csvData = @" John,32,Engineer Sarah,28,Designer Michael,45,Manager "@ $headers = "Name","Age","Occupation" $objects = $csvData | ConvertFrom-Csv -Header $headers $objects
This command adds headers to headerless CSV data. Each object will have the specified property names. The header array must match the number of columns.
Processing CSV with different encoding
When working with CSV files, encoding issues may arise. Use Get-Content's -Encoding parameter to specify the correct encoding. Common encodings include UTF8, ASCII, and Unicode. This ensures special characters are read correctly.
$fileContent = Get-Content -Path "C:\data\employees.csv" -Encoding UTF8 $objects = $fileContent | ConvertFrom-Csv $objects
This command reads a UTF8-encoded CSV file. The -Encoding parameter ensures proper character interpretation. Adjust the encoding type as needed for your specific file.
Filtering converted CSV data
After converting CSV to objects, you can filter them like any PowerShell objects. Use Where-Object to select specific records. This allows powerful data manipulation directly in PowerShell. Filter criteria can use any object property.
$csvData = @"
Name,Age,Occupation
John,32,Engineer
Sarah,28,Designer
Michael,45,Manager
"@
$objects = $csvData | ConvertFrom-Csv
$engineers = $objects | Where-Object { $_.Occupation -eq "Engineer" }
$engineers
This command filters for only Engineer occupations. The Where-Object cmdlet examines each object's Occupation property. Only matching objects are returned.
Exporting converted CSV data
After processing CSV data, you might want to export it. Use Export-Csv to save objects back to CSV format. This creates a new CSV file with the current data. You can specify delimiters and include/exclude headers.
$csvData = @" Name,Age,Occupation John,32,Engineer Sarah,28,Designer Michael,45,Manager "@ $objects = $csvData | ConvertFrom-Csv $objects | Export-Csv -Path "C:\data\processed.csv" -NoTypeInformation
This command saves processed data to a new CSV file. The -NoTypeInformation parameter removes extra type metadata. The output file will contain the modified data in CSV format.
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In this article, we have covered the ConvertFrom-Csv cmdlet in PowerShell.
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