conversion of date from yyyymmddHHMMSS format to yymmddHHMMSS format.

Hi all can anyone please help with the conversion of date from yyyymmddHHMMSS format to yymmddHHMMSS format.

for example I want to change column 1 in the following dataset: (e.g row 1 shoud be 200723000000)

'2020,07,23,00,00,00'	-0.800000000000000
'2020,07,23,00,00,10'	-0.800000000000000
'2020,07,23,00,00,20'	-0.700000000000000
'2020,07,23,00,00,30'	-0.700000000000000
'2020,07,23,00,00,40'	-0.700000000000000
'2020,07,23,00,00,50'	-0.800000000000000
'2020,07,23,00,01,00'	-0.700000000000000
'2020,07,23,00,01,10'	-0.700000000000000
'2020,07,23,00,01,20'	-0.700000000000000
'2020,07,23,00,01,30'	-0.600000000000000
'2020,07,23,00,01,40'	-0.600000000000000
'2020,07,23,00,01,50'	-0.600000000000000
'2020,07,23,00,02,00'	-0.500000000000000
'2020,07,23,00,02,10'	-0.500000000000000
'2020,07,23,00,02,20'	-0.500000000000000
'2020,07,23,00,02,30'	-0.600000000000000
'2020,07,23,00,02,40'	-0.500000000000000
'2020,07,23,00,02,50'	-0.500000000000000
'2020,07,23,00,03,00'	-0.500000000000000
'2020,07,23,00,03,10'	-0.500000000000000
'2020,07,23,00,03,20'	-0.500000000000000

Answer 1

[per isakson]

vec = datevec( '2020,07,23,00,00,00', 'yyyy,mm,dd,HH,MM,SS' );
datestr( vec, 'yymmddHHMMSS' )

ans = '200723000000'

or did you mean

datestr( vec, 'yy,mm,dd,HH,MM,SS' )

ans = '20,07,23,00,00,00'

[Remember Samu]

Thank you , It worked, I meant the first one

[Remember Samu]

Hi per, I am trying the following code for me now to veiw the datevector and I am having an error as shown below. i have attached sample dataset im reading from a txt file.

t = readtable('E:\Data\2020\B220_DT80\20200724T000000.txt');
t(1:8642,:);
height(t);

rng('default') 
dates = t.Var1; 
durations = t.Var2; 
T = table(dates, durations);

fullDateTime = dateshift(T.dates,'start','day') + T.durations;
fullDateTime.Format = 'yyyyMMddHHmmSS';

T.DateTime = datestr(fullDateTime,'yymmddHHMMSS');

T.DNI = t.Var4;

refdata = T(:,{'DateTime','DNI'});
timestampVec1 = datenum(datevec(timestampVec1))

Error using datevec (line 282)

Cannot parse date 200723000000.

Error in test2 (line 18)

timestampVec1 = datenum(datevec(timestampVec1)

[Remember Samu]

hi Per,

so I ran the following code but my date vector is not correct, please see the following:

t = readtable('E:\Data\2020\B220_DT80\20200724T000000.txt');

t(1:8642,:);

height(t);

rng('default')

dates = t.Var1;

durations = t.Var2;

T = table(dates, durations);

fullDateTime = dateshift(T.dates,'start','day') + T.durations;

fullDateTime.Format = 'MM/dd/yyyy HH:mm:ss';

T.DateTime = fullDateTime;

T.DNI = t.Var4;

refdata = T(:,{'DateTime','DNI'});

timestampVec1 = datenum(datevec(T.DateTime))

and when i ran,

datevec(T.DateTime), the following came up it looks like its adding zeros, insted of (2020 07 23 08 52 20), its giving(2.0200 0.0070 0.0230 0.0080 0.0520 0.0202).

2.0200 0.0070 0.0230 0.0080 0.0520 0.0202

2.0200 0.0070 0.0230 0.0080 0.0520 0.0302

2.0200 0.0070 0.0230 0.0080 0.0520 0.0402

2.0200 0.0070 0.0230 0.0080 0.0520 0.0502

2.0200 0.0070 0.0230 0.0080 0.0530 0.0002

2.0200 0.0070 0.0230 0.0080 0.0530 0.0102

2.0200 0.0070 0.0230 0.0080 0.0530 0.0202

2.0200 0.0070 0.0230 0.0080 0.0530 0.0302

2.0200 0.0070 0.0230 0.0080 0.0530 0.0402

2.0200 0.0070 0.0230 0.0080 0.0530 0.0502

2.0200 0.0070 0.0230 0.0080 0.0540 0.0002

2.0200 0.0070 0.0230 0.0080 0.0540 0.0102

2.0200 0.0070 0.0230 0.0080 0.0540 0.0202

2.0200 0.0070 0.0230 0.0080 0.0540 0.0302

2.0200 0.0070 0.0230 0.0080 0.0540 0.0402

2.0200 0.0070 0.0230 0.0080 0.0540 0.0502

2.0200 0.0070 0.0230 0.0080 0.0550 0.0002

2.0200 0.0070 0.0230 0.0080 0.0550 0.0102

2.0200 0.0070 0.0230 0.0080 0.0550 0.0202

2.0200 0.0070 0.0230 0.0080 0.0550 0.0302

2.0200 0.0070 0.0230 0.0080 0.0550 0.0402

2.0200 0.0070 0.0230 0.0080 0.0550 0.0502

2.0200 0.0070 0.0230 0.0080 0.0560 0.0002

2.0200 0.0070 0.0230 0.0080 0.0560 0.0102

[per isakson]

In this case you need to provide a format string. datevec() isn't needed

timestampVec1 = '200723000000';
timestampNum1 = datenum(datevec(timestampVec1,'yymmddHHMMSS'))

timestampNum1 = 737995

timestampNum2 = datenum(timestampVec1,'yymmddHHMMSS')

timestampNum2 = 737995

timestampVec1 is not defined in your script. The last row has little to do with the rest of your script. However,

timestampNum = datenum(datevec(timestampVec1));

Error using datevec (line 289)
Cannot parse date 200723000000.

reproduces the error you report.

[Remember Samu]

hi Per,

so I ran the following code but my date vector is not correct, please see the following:

t = readtable('E:\Data\2020\B220_DT80\20200724T000000.txt');
t(1:8642,:);
height(t);
rng('default') 
dates = t.Var1; 
durations = t.Var2; 
T = table(dates, durations);
fullDateTime = dateshift(T.dates,'start','day') + T.durations;
fullDateTime.Format = 'MM/dd/yyyy HH:mm:ss';
T.DateTime = fullDateTime;
T.DNI = t.Var4;
refdata = T(:,{'DateTime','DNI'});
timestampVec1 = datenum(datevec(T.DateTime))

and when i ran,

datevec(T.DateTime)

the following came up it looks like its adding zeros, insted of (2020 07 23 08 52 20), its giving(2.0200 0.0070 0.0230 0.0080 0.0520 0.0202).

    2.0200    0.0070    0.0230    0.0080    0.0530    0.0002
    2.0200    0.0070    0.0230    0.0080    0.0530    0.0102
    2.0200    0.0070    0.0230    0.0080    0.0530    0.0202
    2.0200    0.0070    0.0230    0.0080    0.0530    0.0302
    2.0200    0.0070    0.0230    0.0080    0.0530    0.0402
    2.0200    0.0070    0.0230    0.0080    0.0530    0.0502
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0002
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0102
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0202
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0302
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0402
    2.0200    0.0070    0.0230    0.0080    0.0540    0.0502
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0002
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0102
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0202
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0302
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0402
    2.0200    0.0070    0.0230    0.0080    0.0550    0.0502
    2.0200    0.0070    0.0230    0.0080    0.0560    0.0002
    2.0200    0.0070    0.0230    0.0080    0.0560    0.0102

[per isakson]

First a couple of comments

• format your question and comments so that they are easier to read an copy
• keep test cases small and to the point, e.g. there is no need for a large text file
• read answers and comments carefully and tell if you don't understand

I added a format string (I'm om R2018b)

%%
t = readtable('20200724T000000.txt');
dates = t.Var1; 
durations = t.Var2; 
T = table(dates, durations);
fullDateTime = dateshift(T.dates,'start','day') + T.durations;
fullDateTime.Format = 'yyyyMMddHHmmSS';
T.DateTime = datestr(fullDateTime,'yymmddHHMMSS');
%%
datevec(T.DateTime(1:2,:),'yymmddHHMMSS')

ans = 2×6

2020 7 23 0 0 0 2020 7 23 0 0 10

The value of T.DateTime is a character array, e.g.

T.DateTime(1:2,:)

ans = 2×12 char array
    '200723000000'
    '200723000010'

Wasn't there a string like 1.0e+4 above the output

format short
magic(4).*1e-6

ans = 4×4

1.0e+-4 * 0.1600 0.0200 0.0300 0.1300 0.0500 0.1100 0.1000 0.0800 0.0900 0.0700 0.0600 0.1200 0.0400 0.1400 0.1500 0.0100

I fail to reproduce your output

datevec(T.DateTime(1:2,:))

Error using datevec (line 289)
Cannot parse date 200723000000.

[Remember Samu]

Thank you so much Per, i needed to pass it in this format (datevec(T.DateTime(1:2,:),'yymmddHHMMSS')) and it worked!