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Powershell Performance: Adding to arrays is slow

A common pattern in many languages adds an element to an array or list

elements = []
for x in range(10000):
 elements.append(x)

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Get-ADUser verses Get-AzureADUser filtering syntax

Get-ADUser -Filter

Filters using Powershell scriptblocks

Ex:

Get-ADUser -Filter "Name -eq 'Fred Johnson'"

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function h1 {
    param([string]$Label)
    "`n#### $label ####`n"
}

$regex = '^(.+?)([^\.]*)$'
$regex_named = '^(?<name>.+?)(?<ext>[^\.]*)$'

h1 "inputs:"
Get-ChildItem c: -File

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example patterns for .gitignore files

These examples assume you created a new repository at c:\projects\cat_translator

Special Characters

character	description
lines starting with '#'	this is a comment, git ignores these lines
*	matches everything except /

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*.pbix

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{
    // example: <https://cdn.discordapp.com/attachments/447476117629304853/797526322200576030/Expand_Aliases_and_Splatting.mp4>
    "powershell.codeFormatting.autoCorrectAliases": true,
    "powershell.codeFormatting.useCorrectCasing": true,
    "powershell.codeFormatting.useConstantStrings": true,
    "files.defaultLanguage": "${activeEditorLanguage}",
    "files.trimTrailingWhitespace": true,
    "terminal.integrated.shell.windows": "C:/Program Files/PowerShell/7/pwsh.exe",
    "terminal.integrated.shellArgs.windows": [
        "-NoLogo"

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// replace bad name
let
    /* ignore this chunk */
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WSspPUtJRMgRiI0NjQxMTpVidaKW0otQUkAgQGxsZm5iZGUPEczOLizPz0kHCQGxibGRqZgSVgphjAtJlbGKqFBsLAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [name = _t, customer = _t, UID = _t]),
    #"Changed Type" = Table.TransformColumnTypes(
        Source,{
            {"name", type text}, {"customer", Int64.Type}, {"UID", Int64.Type}
        }),

    /* select record, modify it, then call Replace

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let
    Source = #"gen DateTimes",

    TableDates = Table.FromList(
        Source,
        Splitter.SplitByNothing(),
        {"SaleDate"},
        null,
        ExtraValues.Error
    ),

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# [test]: only breakpoint in a pipe, not on first statement
Get-PSReadLineKeyHandler -bound -unbound                                # yes
    | ? Group -eq Basic                                                 # no
    | Join-String -seperator ', ' -property Key                         # no
    | Out-Null

# [test] escaped-newline, on the first expression in a pipe             # no
# <<next>> line is                                                      # yes
Get-PSReadLineKeyHandler -bound -unbound `

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Using utf8 in Python

Env vars control unspecified encodings

• locale.GetPrerredEncoding()
• Env var PYTHONIOENCODING

manually forcing utf8 without Env Vars