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Convert String Array to Numeric matrix and string array

Asked by Jochen Petersen on 30 Jun 2019
Latest activity Commented on by dpb
on 30 Jun 2019
Hi! I have a 3 by 15 string matrix. I wish to extract the first and third row as numbers to be assigned to a numerical matrix, while extracting the second row as a row of strings, which are to be assigned to another matrix.
Here is the info:
data_events=
"1" "60" "" "" "" "" "" "" "" "" "" ""
"-" "" "" "" "" "" "" "" "" "" "" ""
"60" "50" "2" "25" "0" "0.2" "0.2" "10" "1000000000" "100000" "100000" "1000000000"
Columns 13 through 15
"" "" ""
"" "" ""
"100000" "100000" "1080"
The idea is to create a matrix Event_Vals, which consists of the stuff in the first and third rows, while another matrix, Event_Comments is to contain the contents of the second row.

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2 Answers

Answer by per isakson
on 30 Jun 2019

Try this
%%
data_events = [
"1" "60" "" "" "" "" "" "" "" "" "" ""
"-" "" "" "" "" "" "" "" "" "" "" ""
"60" "50" "2" "25" "0" "0.2" "0.2" "10" "1000000000" "100000" "100000" "1000000000"
];
%%
Event_Vals = str2double( data_events([1,3],:) );

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Note that you with string arrays (not char arrays), you can simply use double instead of str2double
Event_Vals = double(data_events([1, 3], :))
The same way that to convert numbers to string, you can simply use string:
>> string([1, 2, 3, 4])
ans =
1×4 string array
"1" "2" "3" "4"
+1
I had missed "Unlike the char function, string does not treat numbers as ASCII or Unicode® code points."
Me neither. Having MATLAB act similar to BASIC is not something we're used to...I've yet to play that much with the string class so still discovering such things, too.

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Answer by dpb
on 30 Jun 2019

EventVals=str2double(data_events(1:2:end,:));
EventCmnt=data_events(2,:);

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