MATLAB: Resolved: Need help for using textscan to read a csv file

csvtextscan

Below is my code. I could not find any issues with that. But the results "tmp" are always empty {0x70 cell}.

Please help. Thanks.

====== Code =======

fid = fopen('testfile.csv', 'rt');

formatspec = [repmat('%s ', 1, 70) '%*[^\n]'];

tmp = textscan(fid, formatspec, 1, 'delimiter', ',', 'collectoutput', true, 'headerlines', 16);

fclose(fid);

======= One row of the data file ========== 09FA20010524,09FA20010524,1,2.00105E+17,1,24,2,20010525,0,-44.429,179.9582,1011,989,1000.8,4.531,-999,9,34.307,2,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,2.781,2,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,9,-999,-999,-999,-999,-999,4.45259,27.1871,31.7778,36.2656,40.6526,44.9407

Best Answer

>> s='09FA20010524,09FA20010524,...,31.7778,36.2656,40.6526,44.9407';
>> fmt = [repmat('%s ', 1, 70) '%*[^\n]'];
>> textscan(s, fmt, 1, 'delimiter', ',', 'collectoutput', true)
ans = 
  {1x70 cell}
>> ans{1}
ans = 
Columns 1 through 7
  '09FA20010524'    '09FA20010524'    '1'    '2.00105E+17'    '1'    '24'    '2'
Columns 8 through 14
  '20010525'    '0'    '-44.429'    '179.9582'    '1011'    '989'    '1000.8'
...
Columns 68 through 70
  '44.9407'    []    []
>> length(findstr(s,','))
ans =
  67

Your problem is the last -- there are only 68 fields, not 70 at least in the above record and that combined w/ the last '%*[^\n]' in the format string causes the failure on subsequent lines. Also, lose the extra blank in the format string; it instructs textscan() to try to match an explicit blank of which there are none in the file--I'm a little surprised that didn't cause a failure.

Just use

fmt = repmat('%s', 1, 68);

should be all you need.

Check the input file for consistency in number of columns/record, though, too.

Related Solutions

MATLAB: How to open files based on information from another file

Try this

f = fopen('data.txt');
data = textscan(f, '%f %f %f %f %f %f %f');
fclose(f);
data = [data{:}];
filenames = compose('precip_CZ_%05d_%08d_%04d.dat', data(:,7), data(:,1), data(:,2))

output

>> filenames
filenames =
  6×1 cell array
    {'precip_CZ_02000_20140101_2240.dat'}
    {'precip_CZ_02000_20140101_2250.dat'}
    {'precip_CZ_03000_20140101_1930.dat'}
    {'precip_CZ_04000_20140101_0000.dat'}
    {'precip_CZ_06000_20140101_1600.dat'}
    {'precip_CZ_15000_20140102_2340.dat'}

Read these .dat files using load(), readmatrix() or other similar functions.

MATLAB: Error using textscan to read a csv file with number and text and date in one file

Fan, leave the commas out fo the format and use readtable:

>> t = readtable('test1_V6.csv','Format','%{HH:mm:ss}D%f%C%f%f%f%f%f%f%f%{HH:mm:ss}D%f%f%f%f','Header',3)
Warning: Variable names were modified to make them valid MATLAB identifiers. The original names are saved in the
VariableDescriptions property. 
t =
      Time      Comment    ModuleID    Alt_m_    P_mbar_    T_degC_    x_RH    Wind_degrees_    Wind_m_s_    Supply_V_    UTCTime     Latitude_deg_    Longitude_deg_    Course_deg_    Speed_m_s_
    ________    _______    ________    ______    _______    _______    ____    _____________    _________    _________    ________    _____________    ______________    ___________    __________
    23:09:10    NaN        F667D9      54.2      999.9      16.3       39.2    236              4.1          11.8         23:09:00    70.495           -149.89           78             0.02      
    23:09:11    NaN        F667D9      54.2      999.9      16.3         39    237              3.9          11.8         23:09:05    70.495           -149.89           78             0.01      
    23:09:15    NaN        F667D9      54.2      999.8      16.3       39.1    236              4.1          11.8         23:09:10    70.495           -149.89           78             0.01      
    23:09:20    NaN        F667D9      54.2      999.9      16.3       38.9    236              4.1          11.8         23:09:15    70.495           -149.89           78             0.01      
    23:09:25    NaN        F667D9      54.2      999.8      16.3       38.8    236              3.9          11.8         23:09:20    70.495           -149.89           78             0.02      
    23:09:30    NaN        F667D9      54.2      999.8      16.3       38.7    236              4.1          11.8         23:09:25    70.495           -149.89           78             0.02      
    23:09:32    NaN        F667D9      54.2      999.7      16.3       38.8    236              3.9          11.8         23:09:30    70.495           -149.89           78             0.02      
    23:09:36    NaN        F667D9      54.2      999.8      16.3       39.4    235              4.1          11.8         23:09:35    70.495           -149.89           78             0.01      
    23:09:41    NaN        F667D9      54.2      999.7      16.3       38.8    236              3.9          11.8         23:09:40    70.495           -149.89           78             0.01      
    23:09:46    NaN        F667D9      54.2      999.8      16.3         39    236              4.1          11.8         23:09:45    70.495           -149.89           78             0.01      
    23:09:51    NaN        F667D9      54.2      999.9      16.3       38.8    235              3.9          11.8         23:09:50    70.495           -149.89           78                0      
    23:09:56    NaN        F667D9      54.2      999.8      16.3       39.1    235              4.1          11.8         23:09:55    70.495           -149.89           78             0.01

The times had no date portion, so they were read as "today", but the file header indocates that they're from 6/11/2016. Modify the two time variables accordingly:

>> t.Time = datetime(2016,6,11) + timeofday(t.Time);
>> t.UTCTime = datetime(2016,6,11) + timeofday(t.UTCTime)
t =
            Time            Comment    ModuleID    Alt_m_    P_mbar_    T_degC_    x_RH    Wind_degrees_    Wind_m_s_    Supply_V_          UTCTime           Latitude_deg_    Longitude_deg_    Course_deg_    Speed_m_s_
    ____________________    _______    ________    ______    _______    _______    ____    _____________    _________    _________    ____________________    _____________    ______________    ___________    __________
    11-Jun-2016 23:09:10    NaN        F667D9      54.2      999.9      16.3       39.2    236              4.1          11.8         11-Jun-2016 23:09:00    70.495           -149.89           78             0.02      
    11-Jun-2016 23:09:11    NaN        F667D9      54.2      999.9      16.3         39    237              3.9          11.8         11-Jun-2016 23:09:05    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:15    NaN        F667D9      54.2      999.8      16.3       39.1    236              4.1          11.8         11-Jun-2016 23:09:10    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:20    NaN        F667D9      54.2      999.9      16.3       38.9    236              4.1          11.8         11-Jun-2016 23:09:15    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:25    NaN        F667D9      54.2      999.8      16.3       38.8    236              3.9          11.8         11-Jun-2016 23:09:20    70.495           -149.89           78             0.02      
    11-Jun-2016 23:09:30    NaN        F667D9      54.2      999.8      16.3       38.7    236              4.1          11.8         11-Jun-2016 23:09:25    70.495           -149.89           78             0.02      
    11-Jun-2016 23:09:32    NaN        F667D9      54.2      999.7      16.3       38.8    236              3.9          11.8         11-Jun-2016 23:09:30    70.495           -149.89           78             0.02      
    11-Jun-2016 23:09:36    NaN        F667D9      54.2      999.8      16.3       39.4    235              4.1          11.8         11-Jun-2016 23:09:35    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:41    NaN        F667D9      54.2      999.7      16.3       38.8    236              3.9          11.8         11-Jun-2016 23:09:40    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:46    NaN        F667D9      54.2      999.8      16.3         39    236              4.1          11.8         11-Jun-2016 23:09:45    70.495           -149.89           78             0.01      
    11-Jun-2016 23:09:51    NaN        F667D9      54.2      999.9      16.3       38.8    235              3.9          11.8         11-Jun-2016 23:09:50    70.495           -149.89           78                0      
    11-Jun-2016 23:09:56    NaN        F667D9      54.2      999.8      16.3       39.1    235              4.1          11.8         11-Jun-2016 23:09:55    70.495           -149.89           78             0.01

Best Answer

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