How do I remove leading characters from a string?

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pruth
pruth 2019-9-18
评论： Walter Roberson 2019-9-19
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

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采纳的回答

Walter Roberson
Walter Roberson 2019-9-18
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.
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Walter Roberson
Walter Roberson 2019-9-18
strjoin(segments(2:3), ' ')
Note that we no longer recommend using datenum: we recommend using datetime()

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更多回答（1 个）

Ankit
Ankit 2019-9-18
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
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Ankit
Ankit 2019-9-18
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
Walter Roberson 2019-9-19
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.

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