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

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

[Stephen23]

"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]

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.

Answer 1

[Sara Schulz]

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);

Answer 2

[Shaik]

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.