JSON & CSV

PowerShell · Reference cheat sheet

📋 Overview

PowerShell converts between objects and text formats with ConvertTo-Json / ConvertFrom-Json and Export-Csv / Import-Csv. Prefer object pipelines over hand-rolled string parsing. Watch depth limits and type fidelity when round-tripping JSON.

🔧 Core concepts

PowerShell 7+ improved JSON depth defaults and added -AsHashtable. CSV exports include type metadata comments unless -NoTypeInformation (default in PS 6+).

💡 Examples

JSON:

$data = Get-Content -Raw .\config.json | ConvertFrom-Json
$data.Port = 8080
$data | ConvertTo-Json -Depth 6 | Set-Content -Path .\config.json -Encoding utf8

# PS 7+
$h = Get-Content -Raw .\config.json | ConvertFrom-Json -AsHashtable

CSV:

Get-Process |
  Select-Object Name, Id, CPU |
  Export-Csv .\procs.csv -NoTypeInformation

Import-Csv .\procs.csv |
  Where-Object { [int]$_.Id -gt 1000 }

REST body:

$body = @{ name = 'Ada'; roles = @('dev') } | ConvertTo-Json

⚠️ Pitfalls

• ConvertTo-Json truncates nested objects when -Depth is too low (default historically 2).
• Import-Csv properties are strings—cast numbers/dates explicitly.
• Export-Csv of Format-Table output is wrong—select objects first.
• Hashtable key order / PSCustomObject differences affect JSON shape.
• Large JSON: streaming parsers may be better than loading entirely.
• Encoding: prefer UTF-8 without unexpected BOM issues across tools.

🔗 Related

• objects.md
• rest_api.md
• pipeline.md
• useful_commands.md
• scripting.md