Include rows containing specific value

I have a 1400*9 table (1400 rows and 9 columns) in MATLAB workspace. Each column has a different name. I want to select rows containing specific value. For example, how can I create a new table containig all rows with value of 0.456 in the column named "Biology"? I tried to use following code, but it gave error.

newData=[Data(find(Data.Biology == 0.456, :))]

Answer 1

[Star Strider]

the value you are searching for. 0.456, may not be the exact value.

Use ismembertol instead of find to search for values within the chosen tolerannce.

Example —

Data = array2table(randn(10,9), 'VariableNames',{'A','Biology','C','D','F','G','H','I','J'});
Data{[2 5 9],2} = 0.456 + randn(3,1)*1E-9                   % Create Inexact Values

Data = 10x9 table
       A        Biology         C           D           F            G            H            I           J    
    ________    ________    _________    ________    ________    _________    _________    _________    ________

    -0.56073     0.66848      -1.6558     0.73911    -0.95053     -0.52805      0.73014      0.15877     -1.7607
      1.8967       0.456    -0.074398    -0.19429    -0.13925      -1.0212     -0.78319      -1.2845    -0.21244
       0.457     0.32445     -0.32174    -0.43284    -0.68997      0.23693    -0.046639     0.092096      1.0111
    -0.96723     -2.0929       2.8776     -2.4453      1.2181        4.221       1.6101      -1.4944     0.01197
     -0.1844       0.456       2.1279    -0.77057    -0.18804       1.9395      0.39835    -0.019314    -0.27927
     -0.5154     -2.3019      -1.4235      -1.064     0.82205     -0.75171     -0.43085     -0.74567     -1.2876
    -0.52872       1.059      0.83066    -0.56786      1.5213    0.0041647     -0.29605      0.89714    0.083718
    -0.99425    -0.46588      0.33117    -0.71454     0.64947      0.33089      0.33116     -0.49755      1.2063
    -0.40857       0.456      0.45269     0.35374    -0.11113      0.66758     -0.40103    -0.051921     0.27027
    -0.85864     0.85976      0.74998       1.487     -0.1691       1.3689      -1.0675     -0.26557     0.83313

idx = ismembertol(Data.Biology, 0.456, 1E-4)

idx = 10x1 logical array
   0
   1
   0
   0
   1
   0
   0
   0
   1
   0

numidx = find(idx)

numidx = 3x1

2 5 9

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NewData = Data(numidx,:)

NewData = 3x9 table
       A        Biology        C           D           F           G          H            I           J    
    ________    _______    _________    ________    ________    _______    ________    _________    ________

      1.8967     0.456     -0.074398    -0.19429    -0.13925    -1.0212    -0.78319      -1.2845    -0.21244
     -0.1844     0.456        2.1279    -0.77057    -0.18804     1.9395     0.39835    -0.019314    -0.27927
    -0.40857     0.456       0.45269     0.35374    -0.11113    0.66758    -0.40103    -0.051921     0.27027

The ismembertol function returns a logical vector. To get numeric indices, use find with it.

You may need to adjust the tolerance to work with your data, however this approach should work.

.

[Ninad Varkhede]

Thank you so much. Your solution worked.

[Star Strider]

As always, my pleasure!

Answer 2

[Lei Hou]

rowfilter is used to select rows of a table meeting a specific condition. Here is the code might be useful in your case.

>> rf = rowfilter(Data);
>> Data(rf.Biology==0.456,:)

Hoping this is helpful to you.