How do I remove leading characters from a string?

I read one ascii file. and created this dummy mat file (attached ).

To make simple matrix out of it i need to split the string

i used this code (below) but it coudnt split the first string which is a date and time with some leading number since there is no space in between. There is this number before the date and time, i want remove those numbers so can use datenum on that string !

for i = 1:len_data
    segments = regexp(dummy{1,1}{i,1},' ', 'split');

end

Answer 1

[Walter Roberson]

    segments = regexp(dummy{1,1}{i,1}, '\t', 'split');

Perhaps you could have used readtable() on the ascii file: it would likely have detected the tab delimiter.

[pruth]

Hi walter, thanks for the reply !

your code works fine ! but here even date and time also splits. can you tell me how can just merge 2nd column(date) and 3rd column (time) to use datenum on it !

[Walter Roberson]

strjoin(segments(2:3), ' ')

Note that we no longer recommend using datenum: we recommend using datetime()

[pruth]

that works !

Answer 2

[Ankit]

Hello Pruth,

One possibility is to use extractBetween command.

newStr = extractBetween(str,startPos,endPos)

a = extractBetween(dummy{1, 1}, 10,20)

where 10 is the start position and 20 is the end position.

Based on your requirement you can also try extractAfter, extractBefore

Cheers

Ankit

[pruth]

hi, ankit thanks for the reply !

i used 'extractafter' as you suggested ! it does what I was expecting but i am not able to figure out how convert this cell into normal matrix with 1st coulmn having date and time in matlab format. i want to use datenum here !

i want to create simple matrix.

1st coulmn should be date and time(in matlab format) and next coumns should be data !

I appreciate your help !

[Ankit]

hello pruth,

cell data can be converted to double using str2double. But you can't use it to convert date, it will return a NaN value.

here you can read: Convert Between Datetime Arrays, Numbers, and Text.

thanks

Ankit

[Walter Roberson]

However, datetime() is happy to process cell array of character vectors ;-)

Also, in newer releases, duration() is happy to process cell array of character vectors. This was not possible in older releases.