To join arrays in PowerShell, use the plus operator. It returns a new array with every item from the first array followed by every item from the second: If you want one string instead of one array, use $all -join ‘, ‘. I’ll cover both below, plus the traps I hit when one side holds … Read more
To convert an object to an array in PowerShell, wrap it in the array subexpression operator @(). You always get an array back, even for one object or no objects at all: What “object” means changes the answer, though. Below I cover single objects, PSCustomObject properties, hashtables, command output, and JSON, with the spots where … Read more
To pick random items from an array in PowerShell, pipe the array to Get-Random. Add -Count to get several different items at once: That covers most scripts. Below I’ll show repeats, shuffling, repeatable picks, weighted choices, and the places where Windows PowerShell 5.1 behaves differently from PowerShell 7. How do I pick a random item … Read more
To get unique values from a CSV in PowerShell, import the file and expand one column with the -Unique switch: That’s the whole trick for a single column. The rest of this guide covers sorted lists, duplicate rows, several columns, counts, and the case-sensitivity traps I hit in PowerShell 7 and Windows PowerShell 5.1. How … Read more
PowerShell Format-List shows each property of an object on its own line, which makes wide objects easy to read. Pipe any output to it, or use its alias fl: I tested every example below in PowerShell 7.6 and Windows PowerShell 5.1 with demo employee objects. What does Format-List do in PowerShell? Format-List prints label : … Read more
To get JSON data from a URL in PowerShell, call Invoke-RestMethod. It downloads the response and converts the JSON into objects in one step, so there’s no ConvertFrom-Json to run: I ran every example below in PowerShell 7.6 and Windows PowerShell 5.1 against free public test APIs, so you can paste them as they are. … Read more
To create a folder if it does not exist in PowerShell, check it with Test-Path -PathType Container and run New-Item when the check comes back False: That pattern is safe to run on every script start. Below I cover the -Force shortcut, the .NET method, a reusable function, and two traps I hit while testing … Read more
“Cannot index into a null array” means you used square brackets on a variable that holds $null, so there’s no array to read from. Check the value first, or force it into an array with @(): The real work is finding out why the variable is empty. Below are the usual causes, the fixes I … Read more
To convert a string to a URI in PowerShell, cast it with the [uri] type accelerator. You get a System.Uri object with the scheme, host, path and query already split out: That works the same in PowerShell 7 and Windows PowerShell 5.1. The catch is in the details: the cast doesn’t really validate, and URL … Read more
Need the current time in UTC? In PowerShell 7.1 and later, Get-Date -AsUTC returns it directly. Windows PowerShell 5.1 doesn’t have that switch, so use [datetime]::UtcNow there, which works in every version: Both return a DateTime whose Kind is Utc. Below I’ll format UTC values, convert them to and from US time zones, parse UTC … Read more