Hi David,

Firstly, thank you for your reply.

One condition of my agreeing to undertake PAT was that I got a PAT machine that stored the data, as I am better at programming than paperwork!

I have a Megger PAT 420 which provides a data backup to a USB stick, and thence transfer to my laptop, which is network connected a dual HDD system (Buffalo), which automatically copies the main HDD to the slave HDD.

I found out by accident that the Megger PAT 420 data backup is actually an SQLite database, so that is my route for access. Having played with Python on Raspberry Pi's, I thought I would explore Python for data processing, and now, I have a set of programs which extract SQLite, to 'csv' then collate/process this data and produce a multi-page ODS spreadsheet document, which lists tests by location. I also have an application which extracts appliances requiring testing within a  +/- 30 day window, so I have a target for testing.

My biggest problem is locating kit, and keeping up with removals/disposals and new acquisitions, but the guys are getting a bit better at communication!

I thought it would be useful to the 'management' to have a handle on progress, and stats on tested/new/disposed, etc, hence the latest question.

I convert the datetimestamp to Gregorian ordinal date, as this is easier to use in accessing the resulting 'defaultdict', do the counting and then convert the date back to something comprehensible for writing to an ODS spreadsheet.

Having seen todays posts I am going to look at wxPython, as a front-end (and possibly display?)

Thank you for your consideration


On 12/05/2019 04:20, David L Neil wrote:
Hi Dave,

I also volunteer to do PAT safety testing during my "20% time". Clambering around Snowdonia as a boy, I eschewed* the Rheilffordd yr Wyddfa/SMR in favor of shanks' pony...

* OK, I was made to...! For the good of my soul???

On 9/05/19 8:04 AM, Dave Hill wrote:
I have a csv file which details the results of equipment tests, I carry out PAT testing as a volunteer at a heriatge railway in N. Wales. I want to extract how many items were tested on each test day. So far I have generated a List of test dates, but I am now stalled at how to efficiently count numbers tested on each date.

Can I have a list of tuples, where one item is the date and the second the count?

or is there a better construct?

Thanks in advance,


For completeness, I have listed below an extract from a target file, where the 10 digit number is the UNIX timestamp

182     1515001232
     Toaster     13     2000     1
183     1515001259        Contact Grill     13     2000     1
245     1515001367
     3G Cube Adaptor     13     0     1
246     1515001396         13A IEC Lead     5     0     1
248     1515001415
     Worktop Light     3     30     1
420     1515001440
     Fly killer     0     0     1
424     1515001461
     Dairy fridge     13     0     1
427     1513277293        Fire     13     0     1
429     1515001489
     Toaster Avanti     13     0     1

When you say "target file", is this coming off the tester via a link cable to your PC, or are you capturing by hand to a spreadsheet?

A tactic which many people 'miss' is that a workbook may contain multiple spreadsheets, and that the data on one spreadsheet may be auto-magically 'copied' onto another. Thus if the above is data coming off the PAT into one spreadsheet, I would immediately create a more meaningful sheet, 'for human consumption', which has column headings and converts (re-formats) the timestamp into a readable date (as suggested elsewhere), but is otherwise pretty-much a direct copy. We now have a sheet used for data capture/computer processing and something separate (and prettier) as a report/presentation for people.

From the spec, above, we are only interested in the date. Remember that considering the whole timestamp only makes life confusing. So convert them (only) to dates. These can be strings because Python compares strings as easily as dates!  The time component could be retained if sequence (of testing) might be important.

The sad reality is that a daily count could be accomplished in either LO-Writer or MS-Excel. No reason why you shouldn't use Python though.

(Assuming that the data appears in (forward or reverse) date sequence) Read-in the data sheet/CSV file, row-by-row, taking note of the date of the first data-entry, and starting to count from one. Then increment for each row where the date matches. When the dates don't match, report, reset the counter, and note the new date.

How will you lay-out and present this report? Another spreadsheet? Screen? Paper?

When you say "count numbers tested on each date", the above method will let you know a (single) daily total of tests-performed.

Did you (also) mean that you want to track how many of tests were performed within categories of devices, eg how many toasters on the one day? In which case, further design consideration is required, eg which devices fit into which category and how to match "Toaster" with "Toaster Avanti"...

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