read csv with negative values (blank space between number and minus)

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Sara Schulz
Sara Schulz 2023-5-16
编辑： Sara Schulz 2023-5-16
Hi everyone!
I want to simply read the values in a csv file into an array. The function readtable works good. I only have the issue that some values are negative numbers but not for example -9 but with a blank space like - 9. So the functions reads it at NaN.
I did this:
mydata = readtable("mytable.csv");
Does anybody have an idea how I could still get the right values for the negative ones? Do I have to remove all the blank spaces somehow?
Thank you for any help and all the best,
Sara
  2 个评论
Stephen23
Stephen23 2023-5-16
"Do I have to remove all the blank spaces somehow?"
How many files do you have like this?
If there are only a handful, then use find-and-replace of any reputable text editor (e.g. Notepad++).
Askic V
Askic V 2023-5-16
We need to know how your csv file looks like. I think your problem is due to default limiter in the function readtable.
To my knowledge, default delimiter is any whitespace character and perhaps, this is a reason why you get NaN.

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回答（2 个）

Sara Schulz
Sara Schulz 2023-5-16
编辑：Sara Schulz 2023-5-16
I found the answer here: https://it.mathworks.com/matlabcentral/answers/728593-how-to-replace-specific-text-in-csv-file#answer_607658
You have to use the following code to delete all blank spaces in the csv:
chr = fileread('myfile.csv');
chr = strrep(chr, ' ', '');
fid = fopen('myfile.csv', 'w');
fprintf(fid, '%s', chr);
fclose(fid);
Shaik
Shaik 2023-5-16
Hi Sara!
To address the issue with negative numbers in your CSV file that have a blank space before the negative sign (e.g., "- 9" instead of "-9"), you can preprocess the data before reading it into the table. One approach is to remove the blank spaces from the values before parsing them.

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