How to get values ​​from multiple columns based on the values ​​of one column ?

i have an 85x3 double dataset made up of months, years and timestamps. i want to extract the values from all 3 columns based on month e.g december/12 then create a new variable with just the selected data in the columns that correspond with 12 for years 2007-2014

[Adam Danz]

Since you described the data as double precision, your timestamps must be numeric instead of datetime. Any reason for that? Datatime values are usually more easy to work with. How are you timestamps represented as numeric values?

Answer 1

[Adam Danz]

This is how I imagine your data are organized based on your description.

% [year, month, data, ...] 
data = [repelem((2007:2014)',12,1), repmat((1:12)',8,1), rand(96,5)]

data = 96×7

1.0e+03 * 2.0070 0.0010 0.0010 0.0001 0.0004 0.0008 0.0002 2.0070 0.0020 0.0001 0.0006 0.0003 0.0004 0.0008 2.0070 0.0030 0.0000 0.0002 0.0003 0.0000 0.0001 2.0070 0.0040 0.0002 0.0005 0.0003 0.0003 0.0002 2.0070 0.0050 0.0008 0.0009 0.0003 0.0010 0.0003 2.0070 0.0060 0.0003 0.0007 0.0010 0.0008 0.0005 2.0070 0.0070 0.0005 0.0003 0.0009 0.0009 0.0007 2.0070 0.0080 0.0005 0.0006 0.0004 0.0002 0.0006 2.0070 0.0090 0.0007 0.0009 0.0001 0.0007 0.0010 2.0070 0.0100 0.0002 0.0001 0.0004 0.0001 0.0000

Get all values from column 3 and month 12 with months in column 2 of the data.

%                  v-months  v-column 3
vals = data(data(:,2)==12,   3)

vals = 8×1

0.3673 0.0875 0.5953 0.4585 0.6260 0.8043 0.1210 0.4608