data extract

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Baba
Baba 2011-11-9
I have data in a single column in the following format:
123456-123456.123.abcde
I would like to extract 123456 between - and .

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采纳的回答

Fangjun Jiang
Fangjun Jiang 2011-11-9
str='123456-123456.123.abcde';
num=regexp(str,'-[^\.]*','match');
num=str2double(num{1}(2:end))
Update
a=dir('*.bin');
b={a.name};
c=regexp(b,'-[^\.]*','match');
d=-cellfun(@str2double,c)
d =
200000 200001 200002
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Fangjun Jiang
Fangjun Jiang 2011-11-9
By the way, when I say valid data in MATLAB, I mean you write down something in your question so others can copy and paste to test it in the code. The three lines in your comment are not really valid data in MATLAB. You could provide it as str={'123456-200000.123.bin';'123456-200001.153.bin';'123456-200002.126.bin'}. So when others copy it, they have the data right away in MATLAB to work with.
Baba
Baba 2011-11-9
Alright, no problem.

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更多回答（1 个）

Walter Roberson
Walter Roberson 2011-11-9
t = regexp(str, '-(\d+)', 'tokens');
str2double(t{1}{1})
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Walter Roberson
Walter Roberson 2011-11-9
It is not very different from Fangjun's version, but involves fewer operations. regexp looks through each of the input strings, looking for a pattern of interest. The pattern of interest starts with a "-" and ends just before the first non-digit after that. The () indicate that whatever pattern inside the () is matched is to be recorded separately, so since the pattern is "one or more digits", those digits are recorded separately (i.e., without the leading "-" that was part of the matching pattern.) The 'tokens' parameter says to return the parts that were recorded separately (the "tokens" that the pattern marked as being of interest.)
The list of tokens is returned all in one cell array, and inside the cell array is a list of cell arrays, one per input string; inside there is the character array. The cellfun iterates over all of individual outputs (one per input line) and unwraps a cell array level from what is there and converts the result from text to a double precision number.
Baba
Baba 2011-11-9
Thanks for the explanation.

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