convert string to number

Hi I have a string array as following:

'15:30:00'

'15:30:01'

'15:30:02'

'15:30:03'

'15:30:04'

'15:30:05'

'15:30:06'

ETC.....

I want the out put to be like 153000

153001

153002

153003

etc,

any help

Answer 1

[Jan]

S = {'15:30:00'; '15:30:01'; '15:30:02'};
S = strrep(S, ':', '');
D = sscanf(sprintf('%s ', S{:}), '%d');

[Andrei Bobrov]

D = str2num(datestr(S,'HHMMSS'))

Answer 2

[Sean de Wolski]

s = '15:30:00';
sn = str2double(s(isstrprop(s,'digit')))