How do I replace (or remove) <undefined> with NaN in a categorical array ?

How do I replace (or remove) <undefined> with NaN in a categorical array ? .dat file excerpt is attached. Thanks for any help !

Answer 1

[Cris LaPierre]

<undefined> is the value used for a missing categorical entry. NaN is for missing numerical values.

You can replace missing values using fillmissing

See this answer: https://www.mathworks.com/matlabcentral/answers/495000-replacing-undefined-in-categoricals-or-defining-a-default-value

[Douglas Leaffer]

Thank you Cris. I do not think I can use fillmissing to replace the categorical <undefined> with a number such as zero ( 0 ) ... Is there a way to do that? Or replace with another categorical such as "None"

[Cris LaPierre]

Your table variable source is of type categorical, so you must use a valid categorical data type, which is categorial, char array, or string.

• categorical(0)
• "0"
• "None"

Here is an example that uses "None"

load Table4excerpt.mat
T41.source = fillmissing(T41.source,'constant',"None")

T41 = 40×10 table
          Datetime          Temp     Hum      DP      WS      Deg       Bar      Rain    UFPConc    source
    ____________________    _____    ____    _____    ___    ______    ______    ____    _______    ______

    17-Aug-2016 05:34:44    81.51    78.1    74.05    4.2    245.25    29.848     0       12460     None  
    17-Aug-2016 05:34:45     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:46     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:47     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:48     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:49     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:50     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:51     81.5      78       74      4     247.5    29.848     0       49020     train 
    17-Aug-2016 05:34:52     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:53     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:54     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:55     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:56     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:57     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:58     81.5      78       74      4     247.5    29.848     0       49020     None  
    17-Aug-2016 05:34:59     81.5      78       74      4     247.5    29.848     0       49020     None  

[Douglas Leaffer]

Thank you. My script is fine now