How to convert a column in a table to date format for plotting a time series?

Question

Tom Kristian Hoffmann 2020-12-9

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回答： Eric Sofen 2020-12-11

Dear MATLAB friends

I´m struggling with the conversion of a column to the date format. The cells in the row are written as '2012-09-01T00:00:00.000Z' . I want to convert all the cells in the column to dates that I can use for plotting a time series.

Any handy hints for this issue?

Thank you already in advance!

Regards

Tom

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Answer 1

Harry Laing 2020-12-9

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You can use the datetime function to convert from string to datetime format for plotting. However, the letter T and Z in your string may give you a headache here.

Either manually or via writing a script, replace the T with a space, and remove the Z, then you can send the entire column of data to the datetime function like so:

datetime(Column_of_Time_Strings,'InputFormat','yyyy-MM-dd HH:mm:ss.SSS')
e.g.
datetime('2012-09-01 00:00:00.000','InputFormat','yyyy-MM-dd HH:mm:ss.SSS')
ans=
  datetime
   01-Sep-2012 00:00:00

Assuming all your time strings in the column follow the same format with a letter T and Z, you could use something like the function strrep to replace parts of the string like so:

newStr = strrep('2012-09-01T00:00:00.000Z', 'T', ' ') % This replaces T with a space
newStr = strrep(newStr, 'Z', '') % This replaces Z with no space (nothing)

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Tom Kristian Hoffmann 2020-12-10

Hey Harry,

thank you so much for your fast help! Replacing the letters with space/nothing and then converting the strings to datetime format 'yyyy-MM-dd HH:mm:ss' was succesfull!

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