Multi page html table, by letter, then by number ... possible to handle nested queries?

Question

I had seen a worked example of handling html tables spread across multiple pages where there was a logical number on each page here: http://www.powerpivotblog.nl/nba-team-spending-and-their-results-with-excel-powerpivot-and-data-explorer/
Which requires a two-step solution:
1) to alter the query to use Number.ToText
(page) =>let
    Source = Web.Page(Web.Contents("http://website_url/a-z/a/" & Number.ToText(page))),
    Data0 = Source{0}[Data],
    ChangedType = Table.TransformColumnTypes(Data0,{{ etc etc}})
in
    ChangedType
and then 2) to supply a {1..X} parameter on a separate sheet.
let
    Source = Table.Combine(List.Transform({1..30}, Query))
in
    Source
In my example URL above (http://website_url/a-z/a/1), there is also a changing letter component /a-z/a/1, 2, 3, then /a-z/b/1,2,3 etc...
Is there an equivalent way of setting an {a..z} parameter as an outer loop and combine it with the {1..30} loop, by any chance?
Thanks for your help.
Colum

Answer 1

Here are two ways you can reduce the number of privacy prompts:
1) Use the trick Curt mentions here about reducing the number of prompts.
Basically, add a query that uses a formula like:
= {Web.Contents("http://website/"), Web.Contents("http://someOthersite/")}
Then, set the privacy level of http://website/ to Public. After saving the privacy level, you can discard the query.
2) You can enable Fast Combine, which will disable the privacy checks. I do not recommend this approach in general, and you should only enable Fast Combine if you are certain that you can trust your data sources. Also, be extremely cautious about enabling
Fast Combine on workbooks you did not create.
I recommend the first approach.
Sorry, I did not include the navigation and transformation steps in my approach above. To include those steps, it will be nicer to go with the two-step approach to prevent the last function in Websites from being too messy.
For the first step, we can create a function which, given a letter and a page number, grabs the data from the website and performs some transformations on it. It might look something like this:
let
    Source = (letter, pageNumber) => let
        Page = Web.Page(Web.Contents("http://website/" & letter & "/" & Number.ToText(pageNumber))),
        Data0 = Page{0}[Data],
        ChangedType = Table.TransformColumnTypes(Data0,{{"FIELD1", type text}, {"FIELD2", type text}, {"FIELD3", type text}, {"FIELD4", type text}, {"FIELD5", type text}})
    in
        ChangedType
in
    Source
Let's call this query GetWebsiteContents.
For the second step we can generate all of the letter and number combinations we need, and then call GetWebsiteContents on each combination. That may look like this:
let
     Numbers = {1..5},
     Letters = {"a", "b", "c"},
     CreatePair = (page) => List.Generate(() => 0, each _ < List.Count(Letters), each _ + 1, each {Letters{_}, page}),
     LetterNumberPairs = List.Combine(List.Generate(() => 0, each _ < List.Count(Numbers), each _ + 1, each CreatePair(Numbers{_}))),
     Websites = List.Generate(() => 0, each _ < List.Count(LetterNumberPairs), each _ + 1, each GetWebsiteContents(LetterNumberPairs{_}{0}, LetterNumberPairs{_}{1}))
 in
     Websites
I hope this helps.
-Alejandro (MSFT)