why do I get this error?
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Hey Thats the code I put and the error:
time1 = AIS1(:,end-4:end)
Index in position 2 is invalid. Array indices must be positive integers or logical values.
Could anybody tell me why?
采纳的回答
Image Analyst
2021-9-16
AIS1 has 4 or fewer columns.
s = size(AIS1)
4 个评论
flashpode
2021-9-16
Image Analyst
2021-9-16
For index 2 to be invalid, it means that end-4 is either 0 or negative. It could be 0 if there were exactly 4 columns in AIS1. It would be negative if AIS1 had only 1, 2, or 3 columns. I'm very sure, from the error you gave, that having 4 or fewer columns was the problem. If it weren't, you would not have gotten that error, you would have gotten no error at all, or would have gotten a different error.
Anyway, I'm glad it's working and thanks for Accepting the Answer.
flashpode
2021-9-16
Image Analyst
2021-9-16
If AIS1 is a simple string or character array, you'd do AIS1(end-4:end). If it's an array of strings, say 100 of them, and you wanted only the last 4 characters off each of them in a new 100 element long string where each string is only 4 characters one way is to do this:
% Make an array of strings.
AIS1 = ["1234567", "123456789"]
for k = 1 : numel(AIS1)
% Get this string as a character array.
thisString = char(AIS1(k));
% Get the last 4 characters of this string
% and put into the k'th cell of a cell array.
last4{k} = thisString(end-4:end);
end
% last4 is a cell array where each cell is a character array.
% Convert to a string array if desired:
last4 = string(last4)
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