How to extract all rows that only one columns has a value greater than?

Question

Wolfgang McCormack 2021-5-21

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/836193-how-to-extract-all-rows-that-only-one-columns-has-a-value-greater-than

编辑： Star Strider 2021-5-21

Hi all,

I have a quick question. I have A as a 5000 x 30 table. I want to to see which cells have a value greater than 50 and extract the entire corresponding row. How should I do that?

Thanks in advance.

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Answer 1

Star Strider 2021-5-21

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/836193-how-to-extract-all-rows-that-only-one-columns-has-a-value-greater-than#answer_705333

编辑：Star Strider 2021-5-21

在 MATLAB Online 中打开

One approach —

T1 = array2table(randi(60,15, 7))
T1 = 15×7 table
    Var1    Var2    Var3    Var4    Var5    Var6    Var7
    ____    ____    ____    ____    ____    ____    ____

     9      56      23      12       3       8 
    49       4      59      14      16      41 
    48      13       6      11      53       3 
    33      16      44       6       7      48 
     4      40      40      51      54      52 
     3      46       2       4      57      30 
    43      32       1      26      52      32 
    14      38      55      46       4       9 
     2      20      53       6      32      21 
     4      27       9      22       6       7 
     9      37      35      24      49      37 
    30      14      53      49      23       9 
    16      57      28      27      15      10 
    32      56      49      55      39      38 
    17       7      29      18       8       1 
idx = any(T1{:,:}>50,2);                                    % Logical Row Index
T1_extracted = T1(idx,:)
T1_extracted = 11×7 table
    Var1    Var2    Var3    Var4    Var5    Var6    Var7
    ____    ____    ____    ____    ____    ____    ____

     9      56      23      12       3       8 
    49       4      59      14      16      41 
    48      13       6      11      53       3 
     4      40      40      51      54      52 
     3      46       2       4      57      30 
    43      32       1      26      52      32 
    14      38      55      46       4       9 
     2      20      53       6      32      21 
    30      14      53      49      23       9 
    16      57      28      27      15      10 
    32      56      49      55      39      38 

EDIT — (21 May 2021 at 15:52)

Added timetable operations and result —

T1T = [table(datetime('now')+hours(0:size(T1,1)-1)', 'VariableNames',{'Time'}) T1]
T1T = 15×8 table
            Time            Var1    Var2    Var3    Var4    Var5    Var6    Var7
    ____________________    ____    ____    ____    ____    ____    ____    ____

    21-May-2021 15:50:17     12       9      56      23      12       3       8 
    21-May-2021 16:50:17     37      49       4      59      14      16      41 
    21-May-2021 17:50:17     46      48      13       6      11      53       3 
    21-May-2021 18:50:17     43      33      16      44       6       7      48 
    21-May-2021 19:50:17     57       4      40      40      51      54      52 
    21-May-2021 20:50:17      5       3      46       2       4      57      30 
    21-May-2021 21:50:17     22      43      32       1      26      52      32 
    21-May-2021 22:50:17     56      14      38      55      46       4       9 
    21-May-2021 23:50:17     43       2      20      53       6      32      21 
    22-May-2021 00:50:17     35       4      27       9      22       6       7 
    22-May-2021 01:50:17     28       9      37      35      24      49      37 
    22-May-2021 02:50:17     47      30      14      53      49      23       9 
    22-May-2021 03:50:17     29      16      57      28      27      15      10 
    22-May-2021 04:50:17     15      32      56      49      55      39      38 
    22-May-2021 05:50:17     47      17       7      29      18       8       1 
TT1 = table2timetable(T1T);
idx = any(TT1{:,:}>50,2);                                    % Logical Row Index
TT1_extracted = TT1(idx,:)
TT1_extracted = 11×7 timetable
            Time            Var1    Var2    Var3    Var4    Var5    Var6    Var7
    ____________________    ____    ____    ____    ____    ____    ____    ____

    21-May-2021 15:50:17     12       9      56      23      12       3       8 
    21-May-2021 16:50:17     37      49       4      59      14      16      41 
    21-May-2021 17:50:17     46      48      13       6      11      53       3 
    21-May-2021 19:50:17     57       4      40      40      51      54      52 
    21-May-2021 20:50:17      5       3      46       2       4      57      30 
    21-May-2021 21:50:17     22      43      32       1      26      52      32 
    21-May-2021 22:50:17     56      14      38      55      46       4       9 
    21-May-2021 23:50:17     43       2      20      53       6      32      21 
    22-May-2021 02:50:17     47      30      14      53      49      23       9 
    22-May-2021 03:50:17     29      16      57      28      27      15      10 
    22-May-2021 04:50:17     15      32      56      49      55      39      38 

.

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Answer 2

David Hill 2021-5-21

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/836193-how-to-extract-all-rows-that-only-one-columns-has-a-value-greater-than#answer_705328

在 MATLAB Online 中打开

a=table2array(yourTable);
[idx,~]=find(a>50);
a=a(unique(idx),:);%this should give you what you are looking for

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Wolfgang McCormack 2021-5-21

@David Hill thank you David. Any solution for timetables? because turning the time table to an array will cause a lot of mess for me. It's a sorted table based on time (with a lot of gaps) and turning it to an array won't allow me to use the histogram for monthyl values.

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Answer 3

Image Analyst 2021-5-21

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/836193-how-to-extract-all-rows-that-only-one-columns-has-a-value-greater-than#answer_705338

在 MATLAB Online 中打开

Try this:

% Convert your table tA to a double matrix called dA.
dA = table2array(tA);
% Find out which rows have any values more than 50.
rowsToTextract = any(dA > 50, 2)
% Extract only those rows.  You can get a new double variable
% and/or a new table variable.  I show both ways.
A50 = dA(rowsToTextract, :) % As a double matrix variable
t50 = tA(rowsToTextract, :) % As a table variable