How to convert a Year Month and Date to Day Number?

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Trisha Mae Roque
Trisha Mae Roque on 13 May 2022
Commented: Steven Lord on 13 May 2022
Good Day! I'm a newbie in Matlab.
I want to ask about converting a whole column that are in date format into a day numbers. It has 2 columns and 824 lines, no headlines. I actually thought of adding another row consist of numbers 1 to 824 then removing the date column but i don't know how to do it.
Here's the sample data in csv.
2020-01-30,1.0
2020-01-31,0.0
2020-02-01,0.0
2020-02-02,1.0
2020-02-03,0.0
Here's my desired product
1,1.0
2,0.0
3,0.0
4,1.0
5,0.0
or
2020-01-30,1.0,1
2020-01-31,0.0,2
2020-02-01,0.0,3
2020-02-02,1.0,4
2020-02-03,0.0,5
Thank you in advance.
  2 Comments
Trisha Mae Roque
Trisha Mae Roque on 13 May 2022
It's just reading the file and I'm sorry for that. I don't even know how to access a column without headlines. I know how to use python but matlab is a different ground for me.

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Accepted Answer

KSSV
KSSV on 13 May 2022
Load the data from csv file into MATLAB using readtable
You can convert the dates into date numbers using datenum
  1 Comment
Steven Lord
Steven Lord on 13 May 2022
Rather than using datenum to create serial date numbers I recommend using datetime to create a datetime array. Looking at some sample data:
s = ["2020-01-30"
"2020-01-31";
"2020-02-01";
"2020-02-02";
"2020-02-03"];
theFormat = 'yyyy-MM-dd'; % Use for importing and/or displaying
You can use the default display format, which in this case is different from how the data is stored in the string array s:
dt = datetime(s, 'InputFormat', theFormat)
dt = 5×1 datetime array
30-Jan-2020 31-Jan-2020 01-Feb-2020 02-Feb-2020 03-Feb-2020
Or you can specify your own display format, which displays it in the same form as the strings in s:
dt = datetime(s, 'InputFormat', theFormat, ...
'Format', theFormat)
dt = 5×1 datetime array
2020-01-30 2020-01-31 2020-02-01 2020-02-02 2020-02-03
If you're using release R2019a or later also consider using readtimetable instead of readtable.

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