Problem

In many industries, files are named using conventions that embed useful metadata directly in the file name. For example, in e-commerce, logistics, or billing systems, file names might include prices, order numbers, or other key details.

In my case, I have a folder full of PDF files, each named with a format like Hotel-996.35.pdf, where the last part (996.35) represents the price of this invoice. Now, I want to calculate the total price of all transactions by summing up the prices embedded in these file names. Doing this manually for a large number of files is time-consuming and is easy to make errors.

By using PowerShell, you can quickly extract prices from file names and calculate the total. This blog post show you a PowerShell script that solves this problem efficiently.

Solution

The following PowerShell script below automates the process of extracting prices from file names and calculating their total. 

$directory = Get-Location
$totalPrice = 0
$pdfFiles = Get-ChildItem -Path $directory

foreach ($file in $pdfFiles) {
    if ($file.BaseName -match "-([0-9]+(\.[0-9]{1,2})?)") {
		Write-Host "Found: " $file.Name		
		$unitPrice = [decimal]::Parse($matches[1], [Globalization.NumberStyles]::Float)
        $totalPrice += $unitPrice
    }
}

Write-Host "Total: $totalPrice"

Let’s break down how it works step by step.

1. Working Directory

Get the current working directory using the Get-Location cmdlet. This is the folder where the script will look for files. 

$directory = Get-Location

2. Retrieve Files in the Directory

The Get-ChildItem cmdlet retrieves all files in the specified directory. By default, it fetches all file types, but you can filter it to only include PDF files by adding a -Filter parameter (e.g., -Filter *.pdf).

$pdfFiles = Get-ChildItem -Path $directory

3. Extract the Price Using Regex

The -match operator is used to apply a regular expression (regex) to the file's base name (the file name without extension). The regex pattern -([0-9]+(\.[0-9]{1,2})?) is designed to match a hyphen (-) followed by a number.

  • [0-9]+: Matches one or more digits (e.g., 996).
  • (\.[0-9]{1,2})?: Optionally matches a decimal point followed by 1 or 2 digits (e.g., .35).
  • The entire pattern is enclosed in parentheses to capture the matched number for later use.

If a match is found, the matched value is stored in the $matches automatic variable.

$file.BaseName -match "-([0-9]+(\.[0-9]{1,2})?)"

4. Convert the Price to Decimal

The matched price (stored in $matches[1]) is converted to a decimal number using the [decimal]::Parse() method. 

$unitPrice = [decimal]::Parse($matches[1], [Globalization.NumberStyles]::Float)

5. Add Total Price

$totalPrice += $unitPrice

Conclusion

This PowerShell script provides a simple yet powerful solution to a common problem: extracting numeric data from file names and performing calculations. You can modify it to make it works for your scenarios!