format_match_datetime doesn't handle ISO 8601 (yyyy-mm-dd"T"hh:mm:ss"Z") dates
[NB This issue was originally isolated when attempting to chart these data, but the behaviour is apparently in the handling of the cell data itself. The original text is kept here, but a simpler demonstration is below in the comment on the date2unix(.) function.]
Given a column of dates in the ISO 8601 format (YYYY"-"MM"-"DD"T"hh"-"mm"-"ss(.sss)"Z") which is now supported by default in the cell formatting system, the charting sub-system should handle these as dates (internally can be converted to milliseconds since the epoch of 1970-01-01) not as instances.
- save this data set as example_data.csv:
TimeISO,Wkg 2018-12-14T15:30:04Z,34.72 2018-12-14T15:35:04Z,34.69 2018-12-14T15:40:04Z,34.73 2018-12-14T15:50:04Z,34.79 2018-12-14T15:55:04Z,35.41 2018-12-14T16:05:04Z,35.47 2018-12-14T16:10:04Z,35.48 2018-12-14T16:15:04Z,35.47 2018-12-14T16:25:04Z,35.50 2018-12-14T16:30:04Z,35.50
open file in gnumeric 'gnumeric example_data.csv'
import with only comma ',' as separator
==> gnumeric is open with data in first two columns and first eleven rows
select column A, right-click on column header, select "Format 1 column" from context menu
select 'Date' category, pick last entry [yyyy-mm-dd"T"hh:mm:ss"Z"], click "OK"
==> cells are formatted as date
select columns 'A' and 'B'
click chart icon
==> Chart dialog opens up with 'XY' data type (great) but with x-axis as 0:12 not as dates
I would expect the charting sub-system to recognize the cells as dates and organize the x-axis as a temporal axis.