showing weekdays of dates

using sr pgdoc I searched for weekdays and though I found a few results I
couldn't parse from information provided how to get weekdays of dates to
populate a table in any fashion.  When I do more in depth analysis of
accumulating data sets, some of the analysis I'd like to do would be for
each of the seven weekdays during a period of time.  I ended up with a
script that does two date calls one for the iso date and the second for
weekday number and that script writes out the day's insert statement
correctly with the values it figures out and the values I supply.  The
whole system I have now is for health monitoring blood pressure and blood
sugar numbers and that's how my doctor gets my numbers for checking
progress.  It didn't take long to write, I like to improve it as I learn
new things with which I can improve it.