why does this not work?

>> x='0:07.50 2:03.91 3:57.36 5:09.44 6:32.90 7:43.03 9:43.45';

>> datetime(x,'InputFormat','m:ss.SS')

Error using datetime (line 257)

Unable to convert '0:07.50 2:03.91 3:57.36 5:09.44 6:32.90 7:43.03 9:43.45' to

datetime using the format 'm:ss.SS'.

Answer 1

[Les Beckham]

That doesn't work because your x is one long character vector and datetime tries to match your input format to the entire contents of x. Instead define x as either a string array or a cell array of character vectors.

Using a string array:

x = [ "0:07.50" "2:03.91" "3:57.36" "5:09.44" "6:32.90" "7:43.03" "9:43.45" ];
dt1 = datetime(x,'InputFormat','m:ss.SS')

dt1 = 1x7 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57   27-Mar-2025 00:05:09   27-Mar-2025 00:06:32   27-Mar-2025 00:07:43   27-Mar-2025 00:09:43

Using a cell array of char vectors:

 x= { '0:07.50' '2:03.91' '3:57.36' '5:09.44' '6:32.90' '7:43.03' '9:43.45' };
 dt2 = datetime(x,'InputFormat','m:ss.SS')

dt2 = 1x7 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57   27-Mar-2025 00:05:09   27-Mar-2025 00:06:32   27-Mar-2025 00:07:43   27-Mar-2025 00:09:43

 isequal(dt1, dt2)

ans = logical
   1

Edit:

If you want to convert your datetime array to numeric seconds:

 dt_seconds = 60*minute(dt1) + second(dt1)

dt_seconds = 1×7

7.5000 123.9100 237.3600 309.4400 392.9000 463.0300 583.4500

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Answer 2

[John D'Errico]

It failed because datetime did not recognize that string as a list of distinct times. Just because you know what you want code to do, does not mean it will read your mind. Code is pretty dumb in general.

x='0:07.50 2:03.91 3:57.36 5:09.44 6:32.90 7:43.03 9:43.45';
xspl = strsplit(x,' ')

xspl = 1x7 cell array
    {'0:07.50'}    {'2:03.91'}    {'3:57.36'}    {'5:09.44'}    {'6:32.90'}    {'7:43.03'}    {'9:43.45'}

datetime(xspl,'InputFormat','m:ss.SS') 

ans = 1x7 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57   27-Mar-2025 00:05:09   27-Mar-2025 00:06:32   27-Mar-2025 00:07:43   27-Mar-2025 00:09:43

Answer 3

[Star Strider]

need to separate the elements of the array (that I changed to a cell array here).

Then, it works —

x = {'0:07.50' '2:03.91' '3:57.36' '5:09.44' '6:32.90' '7:43.03' '9:43.45'};
datetime(x,'InputFormat','m:ss.SS')

ans = 1x7 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57   27-Mar-2025 00:05:09   27-Mar-2025 00:06:32   27-Mar-2025 00:07:43   27-Mar-2025 00:09:43

.

EDIT — (27 Mar 2025 at 21:13)

Use timeofday with seconds.

Perhaps this —

x = {'0:07.50' '2:03.91' '3:57.36' '5:09.44' '6:32.90' '7:43.03' '9:43.45'};
dt = datetime(x,'InputFormat','m:ss.SS')

dt = 1x7 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57   27-Mar-2025 00:05:09   27-Mar-2025 00:06:32   27-Mar-2025 00:07:43   27-Mar-2025 00:09:43

dtm = seconds(timeofday(dt))

dtm = 1×7

7.5000 123.9100 237.3600 309.4400 392.9000 463.0300 583.4500

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This works, and there may also be other ways of doing that conversion.

.

Answer 4

[Rob]

I appreciate all the answers, and apologize for not just saying what I want to happen. I want to translate a string array

[ "0:07.50" "2:03.91" "3:57.36"]

into numbers

[0*60 + 7.5, 2*60 + 3.91, 3*60 + 57.36]

ans =

7.5000 123.9100 237.3600

For 3 elements in the string array, doing it manually is fine. But I have dozens.

[Walter Roberson]

S = [ "0:07.50" "2:03.91" "3:57.36"];
DT = datetime(S, "InputFormat", "m:ss.SS")

DT = 1x3 datetime array
   27-Mar-2025 00:00:07   27-Mar-2025 00:02:03   27-Mar-2025 00:03:57

D = seconds(DT - dateshift(DT, 'start', 'day'))

D = 1×3

7.5000 123.9100 237.3600

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[Steven Lord]

Or you can create a duration instead of a datetime and avoid having to do the dateshift.

S = [ "0:07.50" "2:03.91" "3:57.36"];
DT = duration(S, "InputFormat", "mm:ss.SS")

DT = 1x3 duration array
   00:00:07   00:02:03   00:03:57

D = seconds(DT)

D = 1×3

7.5000 123.9100 237.3600

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[Walter Roberson]

Ah, when I tested with duration, I missed that you need to use mm instead of m