Find logical and (&&) for string array

Hi,

I normally use && operations with numeric arrays, like:

if arrayX==1 && arrayY ==2
    z=10
elseif arrayX==2 && arrayY==1
    z=20
end

Now, I'm trying to do the same thing with string arrays, but cannot find the way to do it correctly, the && operand does not work here. Example:

if arrayX=="Left" && arrayY=="Right"
    z=10
elseif arrayX=="Right" && arrayY=="Left"
    z=20
end

Any help with this very much appreciated.

Thanks.

Answer 1

[Steven Lord]

That should work as long as the string arrays you're using in your comparisons are scalars.

arrayX = "Left";
arrayY = "Right";
if arrayX=="Left" && arrayY=="Right"
    z=10
elseif arrayX=="Right" && arrayY=="Left"
    z=20
end

z = 10

arrayX = "Right";
arrayY = "Left";
if arrayX=="Left" && arrayY=="Right"
    z=10
elseif arrayX=="Right" && arrayY=="Left"
    z=20
end

z = 20

It won't work if they're non-scalar string arrays, just like it wouldn't work with numeric arrays if they were non-scalar. I've wrapped each of these code segments in a try / catch block so I can show you the same behavior with both a non-scalar string array and a non-scalar numeric array.

try
    arrayX = ["Left", "Left"];
    arrayY = "Right";
    if arrayX=="Left" && arrayY=="Right"
        z=10
    elseif arrayX=="Right" && arrayY=="Left"
        z=20
    end
catch ME
    fprintf("This code threw error:\n%s\n", ME.message)
end

This code threw error:
Operands to the logical AND (&&) and OR (||) operators must be convertible to logical scalar values. Use the ANY or ALL functions to reduce operands to logical scalar values.

try
    arrayX = [1 2];
    arrayY = 2;
    if arrayX==1 && arrayY ==2
        z=10
    elseif arrayX==2 && arrayY==1
        z=20
    end
catch ME2
    fprintf("This code threw error:\n%s\n", ME2.message)
end

This code threw error:
Operands to the logical AND (&&) and OR (||) operators must be convertible to logical scalar values. Use the ANY or ALL functions to reduce operands to logical scalar values.

Both code segments threw the same error.

Answer 2

[Dyuman Joshi]

Use strcmp or isequal to compare strings

str1 = "Left";
str2 = "Right";
if strcmp(str1,"Left") && strcmp(str2,"Right")
    z=10
elseif strcmp(str1,"Right") && strcmp(str2,"Left")
    z=20
end

z = 10

[Mikel Jimenez]

Thanks Dyuman, this seems to be working too.