check whether a number belongs to an array or not

hi all, i want to check a number in the array.i have created an array and i want to know that a whether a perticular number belongs to the array or not. is there any inbuild function for "belongs to" in matlab. can anybody help me?

Answer 1

[Walter Roberson]

ismember()

Note: if you are not using purely whole numbers, then please read http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[biswajita lenka]

i guess "ismember" is for vectors,nor for array.but i am intrested to check whether a number belongs to an array or not.can you please give me an idea?

[Walter Roberson]

ismember(theValue, YourArray(:))

[biswajita lenka]

thanks,let me try.

[biswajita lenka]

thanks,it works

[Walter Roberson]

Note: later versions of MATLAB added ismembertol() for dealing with floating point numbers.

Answer 2

[Jan]

A = floor(rand(100, 100) * 1000);
contains5 = any(A(:) == 5);

If the array is large and the searched element is found early, Matlab wastes a lot of time by searching the rest of the array. Then this C-Mex is faster: FEX: anyEq.

[Anuchit Wibun]

Hello K. Jan Simon

assume i have many group of array that i want to check it contain 5 whether or not ha within loop. For example: first time, i check A array that it contain 5 yes or not and next, i check B and C, respectively. How i can modify your code? please show sample.

A = [1 10 12 5 4 15 29];
B = [2 23 5 19 28 1 3];
C = [23 5 1 6 29 9];

Thank you every much

[Wasikar]

l_array = [A,B,C];
res = ismember(5,l_array);
disp(res)

[ha ha]

@Jan. Can you teach me how to run FEX: anyEq. as you mentioned? Thanks

[James Tursa]

- Download the code from the provided link

- Compile the code at the command line:

mex anyEq.c -largeArrayDims

- Use the function like any other function. For help on syntax,

help anyEq