Virtual Geek

While working with CSV file I had few column in the true and false boolean value. But when I was importing csv file in PowerShell it was treating them as a string value instead of boolean in the output. Here I will explore how to convert true and false values to boolean.

Method 1

To safely use and convert string value in CSV file to boolean I am using [System.Convert] .net object and its method ToBoolean(). Below is the step by step guide on how to use it.

# If I use true or false and get the type name it shows me Boolean type.
[System.Convert]::ToBoolean('true').GetType()
[System.Convert]::ToBoolean('false').GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Boolean                                  System.ValueType

# If instead of true or false value if I use any other string value it fails with the error.
[System.Convert]::ToBoolean('Yes')
MethodInvocationException: Exception calling "ToBoolean" with "1" argument(s): "String 'Yes' was not recognized as a valid Boolean."

# Here I get the boolean value accordingly.
[System.Convert]::ToBoolean('true')
True
[System.Convert]::ToBoolean('false')
False

# Instead of true or false value you can use 0 for false and any other number for true
[System.Convert]::ToBoolean(0)
False
[System.Convert]::ToBoolean(1)
True
[System.Convert]::ToBoolean(100)
True

If I import csv file and check the member property of pass it shows the type as string. To convert that pass property I am using  foreach object and using [System.Convert]::ToBoolean() method converting pass property value to boolean as it can be seen in the member information earlier and later.

$rawData = Import-Csv -Path "$PSScriptRoot\info.csv"
$rawData | Get-Member -Name Pass
# Name MemberType   Definition
# ---- ----------   ----------
# Pass NoteProperty string Pass=true

$data = Import-Csv -Path "$PSScriptRoot\info.csv" | ForEach-Object {
    $_.Pass = [System.Convert]::ToBoolean($_.Pass)
    $_
}
$data | Get-Member -Name Pass
# Name MemberType   Definition
# ---- ----------   ----------
# Pass NoteProperty bool Pass=True

Method 2  

This is different way and I am using [bool] .net object and Parse() method. 

Download this entire script code here or it is also available on github.

# While boolean parsing you can only use true or false value only.
[bool]::Parse('true').GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Boolean                                  System.ValueType

[bool]::Parse('true')
True
[bool]::Parse('false')
False 

# If you use any other value than true or false it will simply end up with error.

[bool]::Parse(0)
[bool]::Parse('Yes')

MethodInvocationException: 
Line |
   0 |  [bool]::Parse('Yes')
     |  ~~~~~~~~~~~~~~~~~~~~
     | Exception calling "Parse" with "1" argument(s): "String 'Yes' was not recognized as a valid Boolean."

# If you are planning to use number use 0 for false and 1 for true.
[bool]0
[bool]1

Here you can parse a bool value using Select-Object with name and expression. 

$rawData = Import-Csv -Path "$PSScriptRoot\info.csv"
$data = $rawData | Select-Object *, @{Name='Pass_Bool'; Expression={[bool]::Parse($_.Pass)}}

# Student Pass  Pass_Bool
# ------- ----  ---------
# Roman   true       True
# Timothy false     False

$data | Get-Member -Name Pass, Pass_Bool
# Name      MemberType   Definition
# ----      ----------   ----------
# Pass      NoteProperty string Pass=true
# Pass_Bool NoteProperty System.Boolean Pass_Bool=True

Method 3 

$rawData = Import-Csv -Path "$PSScriptRoot\info.csv"
$rawData | Get-Member -Name Pass, IsActive

# Name     MemberType   Definition
# ----     ----------   ----------
# Pass     NoteProperty string Pass=true
# IsActive NoteProperty bool IsActive=True

$rawData = Import-Csv -Path "$PSScriptRoot\info.csv"
$data = $rawData | ForEach-Object {
    #Clean the dollar sign if present, then convert
    $replaceDoller = $_.IsActive.replace('$','')
    $_.IsActive = [System.Convert]::ToBoolean($replaceDoller)
    $_
}

# Student Pass  IsActive
# ------- ----  --------
# Roman   true      True
# Timothy false     False

$data | Get-Member -Name Pass, IsActive

# Name     MemberType   Definition
# ----     ----------   ----------
# Pass     NoteProperty string Pass=true
# IsActive NoteProperty bool IsActive=True