finding rows which correspond to date

I have a table of data with two columns, one with monthly averaged data values and the other with the corresponding month and year in datetime 'MMM yyyy' format, e.g.

Jan 2004    26.3
Mar 2004    27.2
Jun 2004    35.5
Jan 2006    45.1
Mar 2007    32.2

How can I select each row beginning with a specific month eg. March (for each year), to then average these and get a representative average for that month over the full time span?

Many thanks!

[Dom Smith]

The 'table' format doesn't support 'find', so I will keep the two columns as separate files. In which case I need to find the row dependant on month, and then find the corresponding value matching that row within the separate column of numbers

[Peter Perkins]

Dom, you're right that you can't call find on a table, but you can call find on a variable in a table.

find(month(t.Date) == 3)

for example. But usually, you don't want to call find anyway (leave it as a logical)

t(month(t.Date) == 3,:)

And in this case, grouped calculations are already provided as part of varfun.

Answer 1

[Peter Perkins]

>> Date = datetime({'Jan 2004';'Mar 2004';'Jun 2004';'Jan 2006';'Mar 2007'},'Format','MMM yyyy');
>> Value = [26.3;27.2;35.5;45.1;32.2];
>> t = table(Date,Value)
t =
  5×2 table
      Date      Value
    ________    _____
    Jan 2004    26.3 
    Mar 2004    27.2 
    Jun 2004    35.5 
    Jan 2006    45.1 
    Mar 2007    32.2 
>> t.Month = month(t.Date,'shortname')
t =
  5×3 table
      Date      Value    Month
    ________    _____    _____
    Jan 2004    26.3     'Jan'
    Mar 2004    27.2     'Mar'
    Jun 2004    35.5     'Jun'
    Jan 2006    45.1     'Jan'
    Mar 2007    32.2     'Mar'
>> monthly = varfun(@mean,t,'GroupingVariable','Month','InputVariable','Value')
monthly =
  3×3 table
    Month    GroupCount    mean_Value
    _____    __________    __________
    'Jan'        2            35.7   
    'Jun'        1            35.5   
    'Mar'        2            29.7

[Dom Smith]

Legend, thank you kindly!