Select August data from a vector column in the format YYYYMMDD

Hi,

I have two vector columns, one containing the dates in the format YYYYMMDD for 10 years, and in the other column the amount of rainfall in mm. I want to create a matrix, or two vector columns, containing only the months of august with the corresponding rainfall. Any ideas how to achieve this?

Thanks in advance

Answer 1

[Roger Wohlwend]

First convert your time vector into a vector that contains the date as a number.

Date = datenum(Date_Vector,'YYYYMMDD');

Now search for August.

q = month(Date) == 8;

Create your matrix.

AugustRainfallMatrix = [Date(q), Rainfall(q)];

Answer 2

[Peter Perkins]

Are the dates strings, or numbers?

If you have access to R2014b, you could do either of these, depending on which you have:

>> c % cell array of strings
c = 
    '20141201'
    '20141202'
    '20141203'
    '20141204'
    '20141205'
>> month(datetime(c,'Format','yyyyMMdd'))
ans =
    12
    12
    12
    12
    12
>> x % integer values
x =
    20141201
    20141202
    20141203
    20141204
    20141205
>> month(datetime(x,'convertFrom','YYYYMMDD'))
ans =
    12
    12
    12
    12
    12