Regular Expression to timestamp

I have a log file that gives me a timestamp with two formats:

when time is between [0h,1h[:

11:32.456 - MM:SS.zzz

when time is between [1h,1000h[:

22:45:45.234 - HH:MM:SS.zzz

So i created this regular expression:

(?<hour>\d+)?:?(?<minute>\d+):(?<second>\d+)\.(?<fraction>\d+)

The problem is that if the time is less than one hour ( [0h,1h[ - 11:32.456) the regular expression gives me this:

Hour:1

Minute: 1

seconds: 32

fraction: 456

I need the next result:

Hour: 0

Minute: 11

seconds: 32

fraction: 456

If the time is greater than 1 hour all goes fine.

How can i solve this problem?

Thanks.

Answer 1

[Star Strider]

I would just use the hour, minute and second functions.

Note that second will give you the fractions as well.

If you want to separate the fractions:

t1 = datetime('now','Format','dd-MMM-yyyy HH:mm:ss.SSS');
s = second(t1)
fraction = rem(s,1)

[Marco Silva]

Thank you for your advice, however, when my timestamp has the format 11:32.456, I receive the error "Unable to convert '11:32.456' to datetime using the format 'HH:mm:ss.SSS'."

And i cant modify the timestamp because my log file has a several entries

[Star Strider]

My pleasure.

Use a different input format for those times:

t = datetime('11:32.456', 'InputFormat','mm:ss.SSS');

or add hours:

intime = '11:32.456';
newtime = sprintf('00:%s', intime);
t = datetime(newtime, 'InputFormat','HH:mm:ss.SSS');

You can check to see what the format is with the number lf elements returned by strfind:

clns = strfind(timestr, ':')

where ‘timestr’ is the string you are using to create your datetime object. If there is only one element in the result, add the '00:' using the sprintf call first.

[Marco Silva]

Good trick, thank you!

[Star Strider]

My pleasure!

Answer 2

[Stephen23]

>> rgx = '(?<H>\d*)(?(1):)(?<M>\d+):(?<S>\d+)\.(?<F>\d+)';
>> regexp('11:32.456',rgx,'names')
ans = 
    H: ''
    M: '11'
    S: '32'
    F: '456'
>> regexp('22:45:45.234',rgx,'names')
ans = 
    H: '22'
    M: '45'
    S: '45'
    F: '234'