please help me read a csv file

i cannot read files using csvread or dlmread

[Jan]

"Cannot" is not a sufficient description of the occurring problems. Please post your code and show us the error messages or explain the difference between your expectations and the results.

Answer 1

[Friedrich]

Hi,

maybe consider using

 >>uiimport

and let MATLAB do the job for you. You can generate M-Code for reading in the data, e.g.

%%Import data from text file.
% Script for importing data from the following text file:
%
%    C:\Users\fhempel\Desktop\tmp\01012013.CSV
%
% To extend the code to different selected data or a different text file,
% generate a function instead of a script.

% Auto-generated by MATLAB on 2014/04/22 11:37:26

%%Initialize variables.
filename = 'C:\Users\fhempel\Desktop\tmp\01012013.CSV';
delimiter = ',';

%%Read columns of data as strings:
% For more information, see the TEXTSCAN documentation.
formatSpec = '%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%[^\n\r]';

%%Open the text file.
fileID = fopen(filename,'r');

%%Read columns of data according to format string.
% This call is based on the structure of the file used to generate this
% code. If an error occurs for a different file, try regenerating the code
% from the Import Tool.
dataArray = textscan(fileID, formatSpec, 'Delimiter', delimiter, 'MultipleDelimsAsOne', true,  'ReturnOnError', false);

%%Close the text file.
fclose(fileID);

%%Convert the contents of columns containing numeric strings to numbers.
% Replace non-numeric strings with NaN.
raw = repmat({''},length(dataArray{1}),length(dataArray)-1);
for col=1:length(dataArray)-1
    raw(1:length(dataArray{col}),col) = dataArray{col};
end
numericData = NaN(size(dataArray{1},1),size(dataArray,2));

for col=[3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,22,23,27]
    % Converts strings in the input cell array to numbers. Replaced non-numeric
    % strings with NaN.
    rawData = dataArray{col};
    for row=1:size(rawData, 1);
        % Create a regular expression to detect and remove non-numeric prefixes and
        % suffixes.
        regexstr = '(?<prefix>.*?)(?<numbers>([-]*(\d+[\,]*)+[\.]{0,1}\d*[eEdD]{0,1}[-+]*\d*[i]{0,1})|([-]*(\d+[\,]*)*[\.]{1,1}\d+[eEdD]{0,1}[-+]*\d*[i]{0,1}))(?<suffix>.*)';
        try
            result = regexp(rawData{row}, regexstr, 'names');
            numbers = result.numbers;

              % Detected commas in non-thousand locations.
              invalidThousandsSeparator = false;
              if any(numbers==',');
                  thousandsRegExp = '^\d+?(\,\d{3})*\.{0,1}\d*$';
                  if isempty(regexp(thousandsRegExp, ',', 'once'));
                      numbers = NaN;
                      invalidThousandsSeparator = true;
                  end
              end
              % Convert numeric strings to numbers.
              if ~invalidThousandsSeparator;
                  numbers = textscan(strrep(numbers, ',', ''), '%f');
                  numericData(row, col) = numbers{1};
                  raw{row, col} = numbers{1};
              end
          catch me
          end
      end
  end

%%Split data into numeric and cell columns.
rawNumericColumns = raw(:, [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,22,23,27]);
rawCellColumns = raw(:, [1,2,19,20,21,24,25,26]);

%%Replace non-numeric cells with NaN
R = cellfun(@(x) ~isnumeric(x) && ~islogical(x),rawNumericColumns); % Find non-numeric cells
rawNumericColumns(R) = {NaN}; % Replace non-numeric cells

%%Allocate imported array to column variable names
DATE = rawCellColumns(:, 1);
TIME = rawCellColumns(:, 2);
TEMP = cell2mat(rawNumericColumns(:, 1));
RH = cell2mat(rawNumericColumns(:, 2));
WDIR = cell2mat(rawNumericColumns(:, 3));
WSPEED = cell2mat(rawNumericColumns(:, 4));
RAINFALL = cell2mat(rawNumericColumns(:, 5));
APRESSURE = cell2mat(rawNumericColumns(:, 6));
SRAD = cell2mat(rawNumericColumns(:, 7));
EVAP = cell2mat(rawNumericColumns(:, 8));
AN1 = cell2mat(rawNumericColumns(:, 9));
AN2 = cell2mat(rawNumericColumns(:, 10));
AN3 = cell2mat(rawNumericColumns(:, 11));
AN4 = cell2mat(rawNumericColumns(:, 12));
DIG1 = cell2mat(rawNumericColumns(:, 13));
DIG2 = cell2mat(rawNumericColumns(:, 14));
DIG3 = cell2mat(rawNumericColumns(:, 15));
DIG4 = cell2mat(rawNumericColumns(:, 16));
PV = rawCellColumns(:, 3);
BAT = rawCellColumns(:, 4);
ACV = rawCellColumns(:, 5);
LAT = cell2mat(rawNumericColumns(:, 17));
LON = cell2mat(rawNumericColumns(:, 18));
ALTI = rawCellColumns(:, 6);
ELEVATION = rawCellColumns(:, 7);
DEVICEINFO = rawCellColumns(:, 8);
CHECKSUM = cell2mat(rawNumericColumns(:, 19));

%%Clear temporary variables
clearvars filename delimiter formatSpec fileID dataArray ans raw col numericData rawData row regexstr result numbers invalidThousandsSeparator thousandsRegExp me rawNumericColumns rawCellColumns R;

[Soumendra Singh]

Thanks man...it worked for me

Answer 2

[Niklas Nylén]

You can also try with importdata

Answer 3

[Image Analyst]

If you have R2013b or later, try readtable:

t = readtable('01012013.csv');

readtable() is able to handle numeric and non-numeric data on the same line.