Find values per day using a bin width.

Hi. I have an 738x2 catalog that contains days (0,1,2..etc) and earthquake magnitudes. I need to to find the magnitudes per day using a bin width i.e 2.1- 3, 3-4, 4-5, 5-6 and to store them in this format: 2.1-3 3-4 4-5

0 .... .... ....

Any help? Bellow, I attach my catalog. 1 .... .... ....

[Jan]

I do not understand, which format you want. What does the ... mean?

[Anna Sidiropoulou]

Days Magnitude bins

2.1-3 3-4 4-5 5-6

0 34 12 0 1

1 23 34 2 3

2 47 25 3 3

Answer 1

[Cris LaPierre]

A little creativity with groupsummary will get you the data you want. It allows you to group your data by day and by user-defined bin edges, each applied to just the corresponding table variables.

eq = readtable("days_magnitudes.txt");
eqT = groupsummary(eq,{'Var1','Var2'},{'none',[1 3 4 5 6]},'IncludeEmptyGroups',true,'IncludeMissingGroups',true)

eqT = 468x3 table
    Var1    disc_Var2    GroupCount
    ____    _________    __________

     0       [1, 3)          56    
     0       [3, 4)          32    
     0       [4, 5)           2    
     0       [5, 6]           1    
     1       [1, 3)          61    
     1       [3, 4)           6    
     1       [4, 5)           0    
     1       [5, 6]           0    
     2       [1, 3)          37    
     2       [3, 4)          15    
     2       [4, 5)           1    
     2       [5, 6]           1    
     3       [1, 3)          21    
     3       [3, 4)           5    
     3       [4, 5)           0    
     3       [5, 6]           0    

If you want the output to be a matrix with a row for each data, and a column for each bin, you can do that in the following way.

out = [unique(eq.Var1), reshape(eqT.GroupCount,4,[])']

out = 117×5

0 56 32 2 1 1 61 6 0 0 2 37 15 1 1 3 21 5 0 0 4 15 1 0 0 5 12 0 0 0 6 11 2 0 0 7 12 4 0 0 8 12 1 0 0 9 6 0 0 0

[Anna Sidiropoulou]

Thank you, but I have a 2015 version. So any alternative for groupsummary ?

[Cris LaPierre]

You'll need alternatives for much of the code, as readtable will behave differently, and strings were not yet supported. You might be able to use findgroups and splitapply (introduced in R2015b), perhaps in conjunction with discretize (introduced in R2015a). Sorry, but I don't have a 2015 version installed to test it for you.

Any chance you can update? Or use MATLAB Online?

[Anna Sidiropoulou]

Thank you, it worked!