How to Read an Existing Excel File

Enumerate the Excel File Contents

#Load the Excel file into a PSCustomObject
$ExcelFile = Import-Excel "C:\Test\file.xlsx" -WorksheetName "Sheet1" 

Visual of Data Structure

The File C:\Test\file.xlsx contains

After loading this data into $ExcelFile the data is stored like:

Other Common Operations

Load a Column

$SpecificColumn = $ExcelFile."anotherHeader" #loads column with the header "anotherHeader" -- data stored in an array

Load a Row

$SpecificRow = $ExcelFile[1] #Loads row at index 1. Index 1 is the first row instead of 0. 

Map Contents to Hashtable to Interpret Data

Sometimes mapping to a Hashtable is more convenient to have access to common Hashtable operations. Enumerate a Hashtable with the row's data by:

$HashTable = @{}
$SpecificRow= $ExcelFile[2]
$SpecificRow.psobject.properties | ForEach-Object { 
    $HashTable[$_.Name] = $_.Value
}

To then iterate through the enumerated Hashtable:

ForEach ($Key in ($HashTable.GetEnumerator()) | Where-Object {$_.Value -eq "x"}){ #Only grabs a key where the value is "x"
    #values accessible with $Key.Name or $Key.Value
}