consolidating table from years to decades

I have a table of bridges with averages by year, I am trying to consolidate this data to be by decade so the averages of the data in the second column reduced to average of that data by 1990s, 19070s etc.

T = readtable("bridgedata.xlsx");
years = unique(T(:,'YEAR_BUILT'));
G = findgroups(T.YEAR_BUILT);

avgNumLanes = splitapply(@mean,T.TRAFFIC_LANES,G);
avgNumLanes = table(avgNumLanes);
numLanesByYear = [years,avgNumLanes];
avgMaxSpanLength = splitapply(@mean,T.MAX_SPAN_LEN_MT,G);
avgMaxSpanLength = table(avgMaxSpanLength);
spanLengthByYear = [years,avgMaxSpanLength];
avgLength = splitapply(@mean,T.STRUCTURE_LEN_MT,G);
avgLength = table(avgLength);
lengthByYear = [years,avgLength];
avgByYear = [avgNumLanes,avgMaxSpanLength,avgLength];

[Stephen23]

Create a new variable/column in the table for the decade, e.g. DEC_BUILT, and use that to group the table data.

You might consider using GROUPSUMMARY rather than repeating SPLITAPPLY.

If you want more help please upload a sample file by clicking the paperclip button.

Answer 1

[Anurag]

Hi David,

I understand that you want to have your averages computed using “decades” as compared to using “years”. Refer to the following modifications in the code provided by you for doing the same:

T = readtable("bridgedata.xlsx");



% Extract the year information from the YEAR_BUILT column
years = year(T.YEAR_BUILT);

% Define the decades you want to group by
decades = floor(years / 10) * 10;

% Group the data by decade
G = findgroups[NM3] (decades);

% Compute the averages for each attribute
avgNumLanes = splitapply[NM4] (@mean, T.TRAFFIC_LANES, G);
avgMaxSpanLength = splitapply(@mean, T.MAX_SPAN_LEN_MT, G);
avgLength = splitapply(@mean, T.STRUCTURE_LEN_MT, G);

% Create a table with decades and corresponding averages
avgByDecade = table(decades, avgNumLanes, avgMaxSpanLength, avgLength);

% Rename the variable names for clarity
avgByDecade.Properties.VariableNames = {'Decade', 'AvgNumLanes', 'AvgMaxSpanLength', 'AvgLength'};

Find the relevant documentations links for the functions used above here:

• https://in.mathworks.com/help/matlab/ref/findgroups.html
• https://in.mathworks.com/help/matlab/ref/splitapply.html

Hope this helped.

Regards,

Anurag