table calculation for CSV file

first picture is table data that I have to use and I already import it in MATLAB

1. I tried readtable('CSVCWtable3') but MATLAB said Unable to find or open 'CSVCWtable3'. Check the path and filename or file permissions. how can I fix it?
2. What code should I use to add all the valuse in column J? (denote as N)
3. After I calculate N, I want to find percentage of each month like) 3J/N, 4J/N

[dpb]

Totally unable to read with old geezer eyes and nothing can do with an image, anyways...but

BigTotal=sum(CW2table3.Total);
PCTs=CW2table3{:,2:end}./sum(CW2table3{:,2:end});

[kevin Lee]

sorry for small image. The first line is work but second line gave me an error

The end operator must be used within an array index expression.

[dpb]

"sorry for small image. "

So attach the table instead...with the paperclip. The expression should work as written.

[dpb]

Not an image, no. save the variable to a .mat file and attach that; we can do nothing with images except look at them.

But, from a sample table left in the workspace here from a previous answer we can illustrate that the syntax works...

>> tmp
tmp =
  8×3 table
        Mean         MeanVals     MeanUnits
    _____________    _________    _________
    {'200.80 V' }        200.8       V     
    {'22.613 mV'}     0.022613       mV    
    {'200.99 V' }       200.99       V     
    {'3.7514 ms'}    0.0037514       ms    
    {'25.886 ms'}     0.025886       ms    
    {'22.987 mV'}     0.022987       mV    
    {'147.81 mV'}      0.14781       mV    
    {'1.4309 mV'}    0.0014309       mV    
>> tmp{:,2:end-1}./sum(tmp{:,2})
ans =
    0.4995
    0.0001
    0.5000
    0.0000
    0.0001
    0.0001
    0.0004
    0.0000
>> 

Only had one numeric column left instead of multiples, but the tmp{:,2:end-1} syntax with end keywork worked to return the second column.

Answer 1

[Jeremy Hughes]

1. I tried readtable('CSVCWtable3') but MATLAB said Unable to find or open 'CSVCWtable3'. Check the path and filename or file permissions. how can I fix it?

If the file is not in the PWD, you should supply the path and the extension.