ConvertFrom-Csv

Converts object properties in comma-separated value (CSV) format into CSV versions of the original objects.

Syntax

ConvertFrom-Csv
           [-InputObject] <psobject[]>
           [[-Delimiter] <char>]
           [-Header <string[]>]
           [<CommonParameters>]
ConvertFrom-Csv
           [-InputObject] <psobject[]>
           -UseCulture
           [-Header <string[]>]
           [<CommonParameters>]

Description

The ConvertFrom-Csv cmdlet creates objects from CSV variable-length strings that are generated by the ConvertTo-Csv cmdlet.

You can use the parameters of this cmdlet to specify the column header row, which determines the property names of the resulting objects, to specify the item delimiter, or to direct this cmdlet to use the list separator for the current culture as the delimiter.

The objects that ConvertFrom-Csv creates are CSV versions of the original objects. The property values of the CSV objects are string versions of the property values of the original objects. The CSV versions of the objects do not have any methods.

You can also use the Export-Csv and Import-Csv cmdlets to convert objects to CSV strings in a file (and back). These cmdlets are the same as the ConvertTo-Csv and ConvertFrom-Csv cmdlets, except that they save the CSV strings in a file.

Examples

Example 1: Convert processes on the local computer to CSV format

This example shows how to convert the processes on the local computer into CSV format and then restore them to object form.

$P = Get-Process | ConvertTo-Csv
$P | ConvertFrom-Csv

The Get-Process cmdlet sends the processes down the pipeline to ConvertTo-Csv. The ConvertTo-Csv cmdlet converts the process objects to a series of CSV strings. The ConvertFrom-Csv cmdlet converts the CSV strings into CSV versions of the original process objects. The CSV strings are saved in the $P variable.

Example 2: Convert a data object to CSV format and then to CSV object format

This example shows how to convert a data object to CSV format and then to CSV object format.

$Date = Get-Date | ConvertTo-Csv -Delimiter ';'
ConvertFrom-Csv -InputObject $Date -Delimiter ';'

The first command uses Get-Date to send the current date and time down the pipeline to ConvertTo-Csv. The ConvertTo-Csv cmdlet converts the date object to a series of CSV strings. The Delimiter parameter is used to specify a semicolon delimiter. The strings are saved in the $Date variable.

Example 3: Use the header parameter to change the names of properties

This example shows how to use the Header parameter of ConvertFrom-Csv to change the names of properties in the resulting imported object.

$J = Start-Job -ScriptBlock { Get-Process } | ConvertTo-Csv  -NoTypeInformation
$Header = 'State', 'MoreData', 'StatusMessage', 'Location', 'Command', 'StateInfo', 'Finished', 'InstanceId', 'Id', 'Name', 'ChildJobs', 'BeginTime', 'EndTime', 'JobType', 'Output', 'Error', 'Progress', 'Verbose', 'Debug', 'Warning', 'Information'
# Delete the default header from $J
$J = $J[1..($J.count - 1)]
$J | ConvertFrom-Csv -Header $Header

State         : Running
MoreData      : True
StatusMessage :
Location      : localhost
Command       : Get-Process
StateInfo     : Running
Finished      : System.Threading.ManualResetEvent
InstanceId    : a259eb63-6824-4b97-a033-305108ae1c2e
Id            : 1
Name          : Job1
ChildJobs     : System.Collections.Generic.List`1[System.Management.Automation.Job]
BeginTime     : 12/20/2018 18:59:57
EndTime       :
JobType       : BackgroundJob
Output        : System.Management.Automation.PSDataCollection`1[System.Management.Automation.PSObject]
Error         : System.Management.Automation.PSDataCollection`1[System.Management.Automation.ErrorRecord]
Progress      : System.Management.Automation.PSDataCollection`1[System.Management.Automation.ProgressRecord]
Verbose       : System.Management.Automation.PSDataCollection`1[System.Management.Automation.VerboseRecord]
Debug         : System.Management.Automation.PSDataCollection`1[System.Management.Automation.DebugRecord]
Warning       : System.Management.Automation.PSDataCollection`1[System.Management.Automation.WarningRecord]
Information   : System.Management.Automation.PSDataCollection`1[System.Management.Automation.InformationRecord]

The Start-Job cmdlet starts a background job that runs Get-Process. A job object is sent down the pipeline to ConvertTo-Csv and converted to a CSV string. The NoTypeInformation parameter removes the type information header from CSV output and is optional in PowerShell Core. The $Header variable contains a custom header that replaces the following default values: HasMoreData, JobStateInfo, PSBeginTime, PSEndTime, and PSJobTypeName. The $J variable contains the CSV string and is used to remove the default header. The ConvertFrom-Csv cmdlet converts the CSV string into a PSCustomObject and uses the Header parameter to apply the $Header variable.

Example 4: Convert CSV strings of service objects

This example shows how to use the ConvertFrom-Csv cmdlet with the UseCulture parameter.

(Get-Culture).TextInfo.ListSeparator
$Services = (Get-Service | ConvertTo-Csv)
ConvertFrom-Csv -InputObject $Services -UseCulture

The Get-Culture cmdlet uses the nested properties TextInfo and ListSeparator to get the current culture's default list separator. The Get-Service cmdlet sends service objects down the pipeline to ConvertTo-Csv. The ConvertTo-Csv converts the service objects to a series of CSV strings. The CSV strings are stored in the $Services variable. The ConvertFrom-Csv cmdlet uses the InputObject parameter and converts the CSV strings from the $Services variable. The UseCulture parameter uses the current culture's default list separator.

When the UseCulture parameter is used, be sure that the current culture's default list separator matches the delimiter used in the CSV strings. Otherwise, ConvertFrom-Csv cannot generate objects from the CSV strings.

Parameters

-Delimiter

Specifies the delimiter that separates the property values in the CSV strings. The default is a comma (,).

Enter a character, such as a colon (:). To specify a semicolon (;) enclose it in single quotation marks.

If you specify a character other than the actual string delimiter in the file, ConvertFrom-Csv cannot create the objects from the CSV strings and will return the CSV strings.

Type:Char
Position:1
Default value:comma (,)
Accept pipeline input:False
Accept wildcard characters:False
-Header

Specifies an alternate column header row for the imported string. The column header determines the property names of the objects created by ConvertFrom-Csv.

Enter column headers as a comma-separated list. Do not enclose the header string in quotation marks. Enclose each column header in single quotation marks.

If you enter fewer column headers than there are data columns, the remaining data columns are discarded. If you enter more column headers than there are data columns, the additional column headers are created with empty data columns.

When using the Header parameter, omit the column header string from the CSV strings. Otherwise, this cmdlet creates an extra object from the items in the header row.

Type:String[]
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-InputObject

Specifies the CSV strings to be converted to objects. Enter a variable that contains the CSV strings or type a command or expression that gets the CSV strings. You can also pipe the CSV strings to ConvertFrom-Csv.

Type:PSObject[]
Position:0
Default value:None
Accept pipeline input:True (ByPropertyName, ByValue)
Accept wildcard characters:False
-UseCulture

Uses the list separator for the current culture as the item delimiter. To find the list separator for a culture, use the following command: (Get-Culture).TextInfo.ListSeparator.

Type:SwitchParameter
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False

Inputs

System.String

You can pipe CSV strings to this cmdlet.

Outputs

System.Management.Automation.PSObject

This cmdlet returns the objects described by the properties in the CSV strings.

Notes

Because the imported objects are CSV versions of the object type, they are not recognized and formatted by the PowerShell type formatting entries that format the non-CSV versions of the object type.

In CSV format, each object is represented by a comma-separated list of the property values of the object. The property values are converted to strings (by using the ToString() method of the object), so they are represented by the name of the property value. This cmdlet does not export the methods of the object.