MATLAB: Find values per day using a bin width.

Question

Hi. I have an 738×2 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 …. …. ….

Answer 1

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