How to conditionally change values in a table

Hi,

I am wondering to conditionally change values in a table. In the table below, everytime that t.val2 is 3 or 4, I want t.val1 to become NaN. How would I do that ?

val1 = {1, 2, 3, 4, 5, 6, 7, 8, 9}.';
val2 = {1, 3, 2, 1, 1, 4, 1, 1, 3}.';
t1 = table(val1, val2);

Thank you,

Answer 1

[Star Strider]

Try this:

val1 = {1, 2, 3, 4, 5, 6, 7, 8, 9}.';
val2 = {1, 3, 2, 1, 1, 4, 1, 1, 3}.';
t1 = table(val1, val2);
lidx = ([t1.val2{:}] == 3) | ([t1.val2{:}] == 4);
t1.val1(lidx) = {NaN}

producing:

t1 =

  9×2 table

         val1               val2      
    _______________    _______________

    {[1.0000e+000]}    {[1.0000e+000]}
    {[        NaN]}    {[3.0000e+000]}
    {[3.0000e+000]}    {[2.0000e+000]}
    {[4.0000e+000]}    {[1.0000e+000]}
    {[5.0000e+000]}    {[1.0000e+000]}
    {[        NaN]}    {[4.0000e+000]}
    {[7.0000e+000]}    {[1.0000e+000]}
    {[8.0000e+000]}    {[1.0000e+000]}
    {[        NaN]}    {[3.0000e+000]}

[012786534]

Neat. Thank you.

[Star Strider]

As always, my pleasure!

Answer 2

[woahs]

First off, unless you have a particular reason for keeping your values in cell arrays, I'd suggest converting them into just double arrays. After that, you can just use ismember to find where an array contains a value of a set you can specify (e.g. 3, 4 in below example) and set those indices to nan.

t1 = cell2table([val1, val2], 'VariableNames', {'val1', 'val2'});
t1.val1(ismember(t1.val1, [3, 4])) = nan;