It is a bit weird that the iOS 17 update to Charts Framework introduces the simplest graphic - the Pie Chart.  But - Yes! In Xcode 15 we get the Pie Chart.  And it makes a wonderful intro to the powerful Charting Framework.  See Stewart Lynch's YouTube Example code to learn the Charting framework.  And just know the framework goes much deeper than a donut hole.

Selection and PieCharts in iOS 17

How to Modify Swift Charts - a lot of code examples that might remind me of how to change some of the chart diagrams.

Outstanding Questions I've had on the Charts API.  Feel free to solve these for me.

Practicing good Chart Structure

Read the FINE Manual - Charts API is difficult.

Learning to Read the Doc for AxisValueLabel - Example.

If you  are looking  for  a  real-world example; then checkout Stewart Lynch's  Charts Framework 2 - Visualizing Large Data Sets with Bar Charts

He  teaches by  _crafting_ the example  code - you  come  away with a greater understanding of why the  code is written this way.   As apposed to an instructor that  just  types  out the pre-written example code on  a  video.  Compare his  teaching style  to others -  if  you  are like  me, it is a  huge difference!

OK  ... I'd call them Axis Labels...  but  I guess theres lots of value in  labeling  the Marks on  a Chart as... AxisMarks.  Now getting the  labels (marks) to  jump up  into  the plotting area  ... that's  a term called "preset" and  the value of preset  should be "inset" - I've learned to reverse engeneer the  Apple Docs thru pure GRIT.

This code example is Eric Callanan found on his GitHub account.  I managed   to  modify just enough to Inset the AxisMarks  ChartXAxis. It took multiple attempts; but having some  working code  to start from is  priceless.

I've substituted the Weekly  Chart in for the Daily Sparkline chart  &  fetching the data  now takes  20-40 seconds for  12 stocks.   I've  heard that constantly monitoring an app to know when to  optimize code is a smart dev  practice.    My first attempt with this was  on  a Sunday and I killed the  simulator right as it was  refreshing - I'd assumed the  worst, in reality  it was working as  fast as it could go.   Not  weekend related... but  just wait.

To save time...  I will configure up  some preview data to experiment with the  Weekly Charts.

I'm trying to add some X-Axis Grid Lines... now I'm searching Mark's book for that topic.  It doesn't seem he covers that detail.  I'm stuck with the Apple Docs.

"A line that a chart draws across its plot area to indicate a reference point along a particular axis."

I'm attempting to change the number of grid lines on my chart.  I did this some many example/tutorial programs ago.  Can not remember the trick. So I have been searching the Docs...
Maybe I've found it... deep deep into an initializer for: 

AxisMarkValues

"Describes the values the axis markers will present (one for each value)."
It has two methods with keyword "stride".

Well, that was really good in theory and passed the compiler's judgy complaints.  But all in all it didn't function.   See over there - no X-axis values/labels/text (whatever Apple wants to call it).

I had this problem before and it was caused by  .chartXAxis(.hidden) line of code that I checked - commented out now.

While we are here - if you want to limit your Y-axis to a range like this:
.chartYScale(domain: priceMin...priceMax)

Also notice whatever I've done with the grid lines has removed all - even the Y-axis grid lines.

This code will get back the axis labels for Days and Hour... but no grid lines!

        .chartXAxis {

            AxisMarks { value in

                AxisGridLine()

                AxisValueLabel(format: .dateTime.weekday(.narrow).hour(), centered: false)

                //AxisValueLabel(format: .dateTime.month().day().hour(), centered: false)

            }

        }

YouTube channel https://www.youtube.com/watch?v=4utsyqhnS4g
SwiftUI Bar Chart with Customizations

It is a quick high-level intro, but he covers a few of the common APIs that I wanted to know how to use.

It has been a few weeks and I've forgotten most of the Charts API that I thought I should remember.  I guess I have not practice (with positive returns) enough.  Today I'm struggling again with the chart axis labels. 

Looking at some of the example code it appears one should be able to write:

            
  Chart  { ... }

.chartXAxis {

                AxisMarks(values: .automatic(desiredCount: 5)) { _ in

                    AxisGridLine()

                    AxisTick()

                    AxisValueLabel("Quarters.", position: .leading, alignment: .center, spacing: 8)

                }

            }

But Xcode has 4 errors for the above code - which looks very similar to example code I've copied and used before.  The most obvious error and one Xcode is willing to fix is: Incorrect argument labels in call (have 'values:_:', expected 'format:preset:position:values:stroke:')  for AxisMarks().

So why does the compiler allow AxisMarks(values: ...) in one instance and complain in the other?

I cannot figure out the docs meaning... but after reading all the init methods of AxisMarks - I feel this issue may have to do with:
init<Value>(preset: AxisMarkPreset, position: AxisMarkPosition, values: [Value], stroke: StrokeStyle?)

Can someone tell me more... why does this init sometimes get called...  (what does it mean to have the generic Value?

I've also now seen this idiom:

.chartXAxis(content: {

               AxisMarks(position: .top)

           })

A nice article on multiple charts by Danijela Vrzan
Combine charts to create stunning designs with Swift Charts

The overall chart consist of:

• Line Chart

  • Line mark symbols

• Area Chart

  • with Gradient color

• Custom X Axis

• Custom Y Axis scale

• Rule Mark