Vlookup technique in Matlab

I have:

1. Single column array that I converted to table in matlab, which represent RGB values combined in one cell so 255119255 (RRRGGGBBB) -Note: this has 40448352 rows
2. Imported table with 10 columns. Column 2 defines the object corresponding to the RGB combined value also 255119225 format (column 9) - Note: This has about 60 rows

I would like to find each cell value in table (1) and if there is a match to the value in Table 2, Column 9 I want it to give me the name corresponding to that value (found in Table 2 column 2). If no match then 'NAN'.

Thank you!

Answer 1

[Walter Roberson]

[tf, idx] = ismember(table1.Column1, table2.Column9);
results = repmat({'NaN'}, length(tf), 1);  %did you say 'NaN' or NaN ?
results(tf) = table2.Column2(idx(tf));

You will need to adjust for the appropriate column names.

[Vespi]

I wanted NAN in order to represent no match. Ideally I would like to get the nearest value since the RGB combination should represent an object.

I ran the code and cannot figure out the last line

 results(tf) = table2.Column2(idx(tf));

I changed it to results(tf) = Object(idx(tf)); Where object is the name of the column from which I want the object values to be given for the corresponding RGB value.

[Walter Roberson]

You cannot just name a column, you have to name the table as well, like table2.Object

I am not clear as to whether your Object column is numeric or string?

You need to define "nearest", which is something that is not straight forward in colour.

Answer 2

[Kelly Kearney]

My vlookup function does this (using the same method Walter describes, in a nice little wrapper).