Customized datetime format within table

Vic
2023 12 2
2 个回答
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更新时间：2023 12 4
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0 个投票

Hi all,
I am trying to compare 2 tables (for both 1st column is datetime, others are numbers). I am trying to find the common timeperiod between those 2 tables. Unfortunately, days are not the same. My original idea is to convert dates into string and look for matching strings between both tables.
Question:
I am a beginner at Matlab, is there a better way to do it? If not, is there an elegant way to get rid of the 2 loops?
Here is the script for the transformation shown in the workspace
------------------------------------------------------------
A1 = readtable(file_name,'VariableNamingRule','preserve'); clc;
B1 = readtable('Independant variables.xlsx');
for i = 1:height(A1)
A2{i,1} = extractBetween(datestr(A1{i,1}),4,11);
end
for j = 1:height(B1)
B2{j,1} = extractBetween(datestr(B1{j,1}),4,11);
end
------------------------------------------------------------
Thanks and best regards,

3 个评论
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Stephen23
Stephen23 2023-12-2
"My original idea is to convert dates into string and look for matching strings between both tables."
Converting to string is usually a sign that the user is not leveraging the DATETIME class to do its job.
"is there a better way to do it?"
There might be some inbuilt approach using TIMETABLES.
Otherwise MAX & MIN and logical indexing would seem to do what you want.
Walter Roberson
Walter Roberson 2023-12-2
See also overlapsrange -- especially with the second output
Vic
Vic 2023-12-3
Thanks you both for your inputs. It helped me finding a solution to my issue.
Here is the working solution returning an array of boolean values.
--------------------------------------------------------------------
A1 = readtable(file_name,'VariableNamingRule','preserve');
B1 = readtable('Variables.xlsx');
Timeframe1 = table2timetable(A1);
Timeframe2 = timerange(B1.observation_date(1),B1.observation_date(end),'months');
[~,Overlap]= overlapsrange(Timeframe1,Timeframe2);

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 采纳的回答

Vic
Vic 2023-12-3

0 个投票

Thanks you both for your inputs. It helped me finding a solution to my issue.
Here is the working solution returning an array of boolean values.
--------------------------------------------------------------------
A1 = readtable(file_name,'VariableNamingRule','preserve');
B1 = readtable('Variables.xlsx');
Timeframe1 = table2timetable(A1);
Timeframe2 = timerange(B1.observation_date(1),B1.observation_date(end),'months');
[~,Overlap]= overlapsrange(Timeframe1,Timeframe2);

更多回答（1 个）

Peter Perkins
Peter Perkins 2023-12-4
Ran in:

0 个投票

Ran in:
Vic, I think you want synchronize.
tt1 = timetable([1;2;3;4;5],RowTimes=datetime(2023,1:5,1))
tt1 = 5×1 timetable
Time Var1 ___________ ____ 01-Jan-2023 1 01-Feb-2023 2 01-Mar-2023 3 01-Apr-2023 4 01-May-2023 5
tt2 = timetable([6;7;8;9;10],RowTimes=datetime(2023,1:5,[31 28 31 30 31]))
tt2 = 5×1 timetable
Time Var1 ___________ ____ 31-Jan-2023 6 28-Feb-2023 7 31-Mar-2023 8 30-Apr-2023 9 31-May-2023 10
tt3 = synchronize(tt1,tt2,"monthly","firstvalue");
tt3.Time.Format = "MMM-uuuu"
tt3 = 5×2 timetable
Time Var1_tt1 Var1_tt2 ________ ________ ________ Jan-2023 1 6 Feb-2023 2 7 Mar-2023 3 8 Apr-2023 4 9 May-2023 5 10
If you don't want the two timetables joined together, use retime on the second one with the first one's time vector as the target row times.

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