How to extract specific dates from a datetime table?
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I have a datetime table (DATE1.mat) containing some dates from 1984 to 2022 at 10:00 am. I have another date timetable (DATE2.mat) that contains data from 2005 to 2019 at 10:00 am with temperature values. Can anyone please tell me how to find only the dates from DATE2.mat file that belong to DATE1.mat list?
Any feedback will be greatly appreciated!
Les Beckham 2023 年 4 月 19 日
found_date_idx = ismember(datet, B.Time); % logical indexes for dates in datet that are found in B
B_selected = B(found_date_idx, :) % extract the rows from B that match the found dates
その他の回答 (2 件)
Adam Danz 2023 年 4 月 19 日
Datetimes are rounded down to the start of the day using dateshift. Then, ismember finds matches between the two sets of dates.
load DATE1.mat % datet (vector)
load DATE2.mat % B (table)
[isDateMatch, idx] = ismember(dateshift(datet,'start','day'),dateshift(B.Time,'start','day'));
B.Time(idx(isDateMatch)) corresponds with datet(isDateMatch)
This line verifies that they are equal.
isequal(dateshift(B.Time(idx(isDateMatch)),'start','day') , dateshift(datet(isDateMatch),'start','day'))
Eric Sofen 2023 年 4 月 20 日
If you know all the datetimes have 10:00:00 time components and you're just matching dates, timetable subscripting does that directly. Of course, if you're concerned about wanting non-exact matches (e.g. to match things that occur on the same date but not the same time), then the approach suggested by Adam is helpful. Other approaches for dealing with inexact matches may involve retime, timerange, or withtol.