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You need to read Rozhenstein on characteristic functions.

select
sum(case when a < .5 then 1 else 0 end) 'A'
,sum(case when a >= .5 and a < .75 then 1 else 0 end) 'B'
,sum(case when a >= .75 then …

The problem is this: parsing HTML from a variety of sources to create pleasant, easy-to-manipulate spreadsheets. HTML can represent the same data in a variety of ways, even within a single web site. What we have are several layers of parsing; layers which must be linked with increasingly simplified intermediate …

The updates to Building Skills in Object-Oriented Design cover some notes on testing, Agility and rework, two ongoing themes that can't be emphasized enough.

There were two small updates regarding testability.

First, creating Outcome instances — for testing purposes — does involve an ugly hack of repeating the payout odds. Since we're …

Don't ask why. I can't explain it without violating a Non-Disclosure Agreement.

However, check this out. Search for NMEA Checksum VB.

• http://www.experts-exchange.com/Databases/GIS_GPS/Q_21413235.html
• http://www.codepedia.com/1/Calculating+and+Validating+NMEA+Checksums
• http://www.codepedia.com/1/Taking+Out+the+Garbage:+NMEA+Checksums …

The star schema represents data as a table of facts (measurable values) that are associated with the various dimensions of the fact. Common dimensions include time, geography, organization, product and the like. I'm working with some folks whose facts are a bunch of medical test results, and the dimensions are …

See the Electric Skateboard in XKCD. "You don't realize how much time you were spending on the boring parts until you don't have to do them anymore."

A helpful answer to "Why is Python so cool?" Fewer Boring Parts.

Many, many thanks to readers who sent in comments, questions, suggestions and corrections.

I've updated Building Skills in Python to correct the errors found so far.

Also, in the process, I've revised chapter 36 a bit.

Some recent thoughts on using Python, directly, as configuration file syntax. In a way, a configuration is a highly-specialized Domain Specific Language focused on the application's problem domain. The point is to leverage syntax we already have to create meaningful configuration files.

"Python is sometimes a good use for a …

See Michael Hugos "Think about screens and the data on them to simplify system development " for some helpful insight on what an "application" really is -- access to data. Simple transparency is lifted up as a critical value for software.

I liked the "If you don't believe it could be this …

Back in December, I posted "I haven't written a program in years ..." with a tidy little example, suitable for someone who used to program. The intent was to help them get a quick program written, leveraging their legacy skills using new tools.

And (bonus to me) it helps me to …