deleting table above a specific row

if i have a table and it has 05 columns.

if i want that when column 3 has a value 25, then delete all the rows above it.

and similarly if column 4 has a value 30, then delete the rows in all the columns below this value.

Answer 1

[KSSV]

% Demo example 
x = (1:100)' ;
y = rand(size(x)) ;
T = table(x,y) ; 
% remove rows which have values greater than 0.7 values
idx = T.(2)>0.7 ;
% remove the rows
T(idx,:) = [] ;

[VBBV]

Zero indexing works for Logical arrays in MATLAB, but doesn't work for numeric arrays. Quite Interesting :)

Answer 2

[Image Analyst]

Try this:

col12 = (1:5)';
col34 = [1,2,25, 30, 1000]';
t = table(col12, col12, col34, col34)

t = 5×4 table
    col12    col12_1    col34    col34_1
    _____    _______    _____    _______

      1         1          1         1  
      2         2          2         2  
      3         3         25        25  
      4         4         30        30  
      5         5       1000      1000  

% Find last row where column 3 is exactly 25
row25 = find(t{:, 3} == 25, 1, 'last')

row25 = 3

% Delete rows above that row25
t = t(row25 : end, :)

t = 3×4 table
    col12    col12_1    col34    col34_1
    _____    _______    _____    _______

      3         3         25        25  
      4         4         30        30  
      5         5       1000      1000  

% Find first row where column 4 is exactly 30
row30 = find(t{:, 3} == 30, 1, 'first')

row30 = 2

% Delete rows below that row30
t = t(1 : row30, :)

t = 2×4 table
    col12    col12_1    col34    col34_1
    _____    _______    _____    _______

      3         3        25        25   
      4         4        30        30