Index exceeds matrix dimensions.

Question

Jovos 2016-2-18

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/268906-index-exceeds-matrix-dimensions

回答： Walter Roberson 2016-2-18

data.txt

Hi, I'm trying to read the raw data from a txt file. Read the file as an array of strings. Then transfer string to num and get the year data. But it shows that the index exceeds matrix dimensions. Anyone help?

filename = input('Please enter the file name: ');
fid01 = fopen(filename,'r');
for i = 6 : 414
    line = fgets(fid01);
    z = strread(line,'%s');
    year = str2num(z{1});
    disp(year)
end

[EDITED, Jan, Code formatted]

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Answer 1

Walter Roberson 2016-2-18

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You have an empty lines in the input, and lines that have only blanks. fgets() is going to return each line including the line terminator. The strread() with '%s' format is going to return an empty cell array on those lines.

I would remind you that

for i = 6 : 414
  line = fgets(fid01);
  ...
end

contains no instructions to MATLAB that the line to be fetched is the line number the corresponds to "i".

What you should do is, before the "for i = 6" loop, add a loop

for i = 1 : 5
  line = fgets(fid01);
end

to read through (and ignore) lines 1 to 5. Then each time you read a line in "for i = 6 : 414" the line number will implicitly synchronize with the value of the "i" variable.