How to convert time column to from HH:MM:SS to minutes and seconds?

I have a doubt , I want to convert Time column ( HH:MM:SS) to min, there is a direct command time2num but it requires toolbox and it's paid.So without using time2num how can I convert into minutes. I tried with datetime also but I got error.

table=readtable('sample.csv'):
times = datetime(table.Time,'InputFormat','HH:mm:ss:SSS');

times = hour(times).*60 + minute(times) + second(times)./60; 

Answer 1

[Chunru]

% table=readtable('sample.csv'):
A=readtable('sample.csv')       % table is a function name in matlab

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

A = 621×4 table
    StoreNo_         Date           Time      Millisecond
    ________    ______________    ________    ___________

        2       {'2020/09/16'}    09:19:04        87     
        3       {'2020/09/16'}    09:19:06        88     
        4       {'2020/09/16'}    09:19:08        88     
        5       {'2020/09/16'}    09:19:10        88     
        6       {'2020/09/16'}    09:19:12        86     
        7       {'2020/09/16'}    09:19:14        91     
        8       {'2020/09/16'}    09:19:16        91     
        9       {'2020/09/16'}    09:19:18        92     
       10       {'2020/09/16'}    09:19:20        92     
       11       {'2020/09/16'}    09:19:22        96     
       12       {'2020/09/16'}    09:19:24        96     
       13       {'2020/09/16'}    09:19:26        97     
       14       {'2020/09/16'}    09:19:28        89     
       15       {'2020/09/16'}    09:19:30        89     
       16       {'2020/09/16'}    09:19:32        90     
       17       {'2020/09/16'}    09:19:34        90     

class(A.Time)       % A.Time is duration and it is not the time 

ans = 'duration'

%times = datetime(A.Time,'InputFormat','HH:mm:ss:SSS')
% times = hour(times).*60 + minute(times) + second(times)./60; 

% you are finding minutes from A.Time
t_minutes = minutes(A.Time)

t_minutes = 621×1

559.0667 559.1000 559.1333 559.1667 559.2000 559.2333 559.2667 559.3000 559.3333 559.3667

[Arshey Dhangekar]

thank you