Script to gather Groups membership by user in Office365

Get-GroupsMemberByUser.ps1

<#
.Synopsis
   Gather groups membership by user in all O365 Tenant.
   Medium Article: https://j0rt3g4.medium.com/report-with-all-the-group-membership-by-the-user-in-office-365-ca48a2398072
.DESCRIPTION
   Gather the membership by user in all O365 Groups
.EXAMPLE
   .\Get-GroupsMemberByUser.ps1
   Get the membership saved into Variable $Report and show it on screen
.EXAMPLE
   .\Get-GroupsMemberByUser.ps1 -CSV
   Get the membership saved into Variable $Report and export it into the Desktop of the current logged user with the given name: DEfault Name GroupsByUsers.csv
.INPUTS
   Any of the following sets:
    Set1:
        -CSV Switch parameter (true or false)
        -Filename Output filename on Desktop

    Set2: Default
        -Screen to gather the results on screen
        
.OUTPUTS
   Screen or CSV File
.NOTES
   Jose Ortega - https://j0rt3g4.medium.com
.COMPONENT
   The component this cmdlet was a solution for a ticket.
.ROLE
   This CMdlet doesn't have any role
.FUNCTIONALITY
   Report on Screen or CSV the group membership in an O365 tenant
#>

[Cmdletbinding(DefaultParameterSetName="Default")]
param(
    [Parameter(Mandatory=$false,ValueFromPipeline=$true,Position=0,ParameterSetName="File")][switch]$CSV=$true,
    [Parameter(Mandatory=$false,ValueFromPipeline=$true,Position=1,ParameterSetName="File")]$FileName="GroupsByUsers.csv",
    [Parameter(Mandatory=$false,ValueFromPipeline=$true,Position=0,ParameterSetName="Default")][switch]$screen=$true
)

#connect or install
try{
    Get-MsolUser -ea Stop | select -First 1 | Out-Null
}
catch{
    try{
        Connect-MsolService -ea Stop | Out-Null
    }
    catch{
        Install-Module MSOnline
        Connect-MsolService
    }
}

#functions
function IsAMember{
    [CmdletBinding()]
    param(
        [Parameter(Mandatory=$true,Position=0,ValueFromPipeline=$true)]$user,
        [Parameter(Mandatory=$true,Position=1,ValueFromPipeline=$true)]$group
    )

    foreach($member in $(Get-MsolGroupMember -GroupObjectId $group.ObjectId)){
        if($user -eq $member.emailAddress){
            return $true
        }
    }
}

#Final Report Variable
$Report = @()
#Gather all users in Tenant - Except the Guests ones (#EXT#)
$AllUsers = Get-MsolUser | where{ $_.UserPrincipalName -notlike "*#EXT#*"} | select -ExpandProperty USerPrincipalName
#Gather All groupps in tenant
$Allgroups=Get-MsolGroup | select ObjectId,DisplayName

Write-Progress -Activity "Creating Report" -PercentComplete 0 -Id 1
$i=0;

foreach($email in $AllUsers){
    $i++
    $x =($i/ $AllUsers.Count) * 100
    
    Write-Progress -Activity "Creating Report" -PercentComplete $x -Id 1
    Write-Progress -Activity "Working with User $email" -PercentComplete 25 -ParentId 1

    Write-Host -ForegroundColor Gray "Working with user $email"
    #cleanupgroups
    $groups=@()
    foreach($g in $Allgroups){
        if(IsAMember -user $email -group $g){
            $groups+= $g.DisplayName
        }
    }
    Write-Host -ForegroundColor Green "Finished with user $email"
    Write-Progress -Activity "Working with User $email" -PercentComplete 100 -ParentId 1 -Completed
    $Report+= New-Object -TypeName PSObject -Property @{"User" = $email; "GroupMembership" = $groups -join ';'}
}

Write-Progress -Activity "Creating Report" -PercentComplete 100 -Id 0 -Completed 


#OnScreen
if($screen){
    $Report
}

if ($CSV){
    $Report | Export-Csv -Path "$env:userprofile\desktop\$FileName" -NoTypeInformation
}

Medium Article:
https://j0rt3g4.medium.com/report-with-all-the-group-membership-by-the-user-in-office-365-ca48a2398072