matlab table timestep calculation

Question

Is there a way to access the column data without having to type table_name.VariableName (:,:)? I need to find the delta time from the time stamp of the data. This is what I have done so far:

[u,v]=size(a);
b=cell2table(cell(u,1));

for i=1:u
   if i==1
       b(i,1)={'0'};
   else
       b(i,1)=(datenum(a.PCTimestamp_None_(i,1)) ...
           -datenum(a.PCTimestamp_None_(i-1,1)))+str2double(b{i-1,1});
   end
end

The problem, I am having is, the time stamp is always in column 1. So I am looking for a way to access data just by mentioning first column instead of variable name.

Any help would be appreciated.

Answer 1

您可以使用花括号来索引表，而无需指定与目标列关联的变量名。卷曲括号也可用于更直接地分配/检索内部单元格值。

[u,v] = size(a);

b = cell(u,1);
b{1} = 0;

for i = 2:u
    b{i} = (datenum(a{i,1}) - datenum(a{i-1,1})) + b{i-1};
end

b = cell2table(b);

Answer 2

表变量可以通过索引t.(1)以及名称

来访问

t = table(ones(3, 1), rand(3, 1), 'VariableNames', {'foo', 'bar'});
assert(isequal(t.bar, t.(2)));