Finding largest data from table

Question

Sebastian Daneli 2021-11-15

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链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1586849-finding-largest-data-from-table

编辑： Seth Furman 2021-11-16

Lets say that I have a table containing three matricies of different lengths.

X1=[9 6 9 0;3 2 7 0];
X2=[0 2;4 0];
X3=[3 1 2; 8 9 7];
X=table(X1,X2,X3)
X = 2×3 table
           X1             X2          X3     
    ________________    ______    ___________

    9    6    9    0    0    2    3    1    2
    3    2    7    0    4    0    8    9    7

How can i I find the longest one? Is there a way to find more then one matrix of a specific lenght? Lets say the ones that are the longest.

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Chunru 2021-11-15

Show what the data you have by giving a minimum example.

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Answer 1

Chunru 2021-11-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1586849-finding-largest-data-from-table#answer_831659

编辑：Chunru 2021-11-15

在 MATLAB Online 中打开

X1=[9 6 9 0;3 2 7 0];
X2=[0 2;4 0];
X3=[3 1 2; 8 9 7];
X4 = X1;
X=table(X1,X2,X3,X4)
X = 2×4 table
           X1             X2          X3                X4       
    ________________    ______    ___________    ________________

    9    6    9    0    0    2    3    1    2    9    6    9    0
    3    2    7    0    4    0    8    9    7    3    2    7    0
len = table2array(varfun(@(x) size(x, 2), X));
% max will find 1 entry only
[lmax, idx] = max(len)
lmax = 4
idx = 1
% if you want multiple entries
idxall = find(len == lmax)
idxall = 1×2
     1     4

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Sebastian Daneli 2021-11-15

Thx

Seth Furman 2021-11-16

编辑：Seth Furman 2021-11-16

在 MATLAB Online 中打开

The only thing I would add is that

@(x) size(x, 2)
ans = function_handle with value:
    @(x)size(x,2)

can be replaced with

@width
ans = function_handle with value:
    @width

since the width function returns the number of variables in a table or the number of columns in an array.

e.g.

X1 = [9 6 9 0;3 2 7 0];
X2 = [0 2;4 0];
X3 = [3 1 2; 8 9 7];
X4 = X1;
X = table(X1,X2,X3,X4)
X = 2×4 table
           X1             X2          X3                X4       
    ________________    ______    ___________    ________________

    9    6    9    0    0    2    3    1    2    9    6    9    0
    3    2    7    0    4    0    8    9    7    3    2    7    0
varfun(@width, X, "OutputFormat", "uniform")
ans = 1×4
     4     2     3     4