JSON operations (ConvertFrom-Json, ConvertTo-Json) in PowerShell - Step-by-Step Execution

Concept Flow - JSON operations (ConvertFrom-Json, ConvertTo-Json)

Start with JSON string

↓

Use ConvertFrom-Json

↓

Get PowerShell object

↓

Modify or use object

↓

Use ConvertTo-Json

↓

Get JSON string output

↓

End

This flow shows how a JSON string is turned into a PowerShell object, used or changed, then turned back into JSON text.

Execution Sample

PowerShell

$json = '{"name":"Anna","age":30}'
$obj = $json | ConvertFrom-Json
$obj.age = 31
$newJson = $obj | ConvertTo-Json
$newJson

This code converts a JSON string to an object, changes the age, then converts it back to JSON.

Execution Table

Step	Action	Input	Output	Notes
1	Assign JSON string to $json	{"name":"Anna","age":30}	{"name":"Anna","age":30}	Raw JSON text stored
2	ConvertFrom-Json to object	$json	Object with properties name='Anna', age=30	JSON parsed into PowerShell object
3	Modify object property	$obj.age = 31	Object with age=31	Age property updated
4	ConvertTo-Json from object	$obj	{ "name": "Anna", "age": 31 }	Object converted back to JSON string
5	Output $newJson	$newJson	{ "name": "Anna", "age": 31 }	Final JSON string output

💡 Process ends after outputting the updated JSON string.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4
$json	{"name":"Anna","age":30}	{"name":"Anna","age":30}	{"name":"Anna","age":30}	{"name":"Anna","age":30}
$obj	null	Object{name='Anna', age=30}	Object{name='Anna', age=31}	Object{name='Anna', age=31}
$newJson	null	null	null	{ "name": "Anna", "age": 31 }

Key Moments - 2 Insights

Why do we need ConvertFrom-Json before changing properties?

Because JSON text is just a string. ConvertFrom-Json turns it into an object we can change, as shown in step 2 and 3.

What happens if we skip ConvertTo-Json at the end?

Without ConvertTo-Json, we keep the object, not JSON text. Step 4 shows converting back to JSON string for output or saving.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of $obj.age after step 3?

A 30

B 31

C null

D Undefined

💡 Hint

Check the 'Output' column in row for step 3 in execution_table.

At which step does the JSON string become a PowerShell object?

A Step 1

B Step 4

C Step 2

D Step 5

💡 Hint

Look for 'ConvertFrom-Json' action in execution_table.

If we change $obj.name to 'Bob' after step 3, what will $newJson contain after step 4?

A {"name":"Bob","age":31}

B {"name":"Bob","age":30}

C {"name":"Anna","age":31}

D {"name":"Anna","age":30}

💡 Hint

Think about the object properties before ConvertTo-Json in step 4.

Concept Snapshot

ConvertFrom-Json: turns JSON text into a PowerShell object.
Modify object properties directly.
ConvertTo-Json: turns object back into JSON text.
Use these to read, change, and save JSON data in scripts.

Full Transcript

This lesson shows how to work with JSON in PowerShell. First, you start with a JSON string. Using ConvertFrom-Json, you turn that string into a PowerShell object. This object lets you access and change data easily, like changing the age property. After changes, use ConvertTo-Json to turn the object back into a JSON string. This string can be saved or sent somewhere. The execution table traces each step: storing the JSON string, converting it to an object, changing the object, converting back to JSON, and outputting the result. Variables like $json, $obj, and $newJson change as the script runs. Key moments explain why conversion is needed before and after changes. The quiz checks understanding of when and how these conversions happen and what the final JSON looks like after changes.