Operands to the || and && operators must be convertible to logical scalar values.

So I don't understand the reason why I am getting the following error:

riskUserId=[];
if (data.A>5) || (data.B==1)
    C=data.D;
end

data is a table

A is of type double

B is of type logical (0s and 1s)

I am still getting used to this table logic and cell content type of data.

[Geoff Hayes]

@Mehdi Jaiem - if data is a table, then what does this mean to you

data.Age>60

? Should there be one age greater than 60 or all ages greater than 60?

[Mehdi Jaiem]

Well actually data.Age accesses all the column Age in the table Data

Name First Name User_ID Contact_ID Infection Preexisting_Conditions Age

____________ ______________ __________ ____________ _________ ______________________

{'Maier' } {'Alfred' } 1e+05 {1×5 double} true false 70

{'Schulz' } {'Petra' } 1e+05 {[ 100017]} false false 64

{'Schmidt' } {'Dieter' } 1e+05 {1×2 double} false false 58

{'Meier' } {'Benjamin' } 1e+05 {[ 100012]} false false 52

{'Gross' } {'Michael' } 1.0001e+05 {1×5 double} true false 46

{'Klein' } {'Nadja' } 1.0001e+05 {1×2 double} false false 40

when I use data.Age I should get the column age as output.

What I am trying to do is to save all User_IDs fulfilling the above mentioned 2 conditions with an "OR" statement in between.

Answer 1

[Cris LaPierre]

Use || and && when you are comparing a single (scalar) value. Use | and & when you are comparing arrays (when there is more than 1 output of the comparison).

a = 1:4;
b = 4:-1:1;
% Works
c = a>2 & b<=3

c = 1×4 logical array
   0   0   1   1

% Error you are seeing
d = a>2 && b<=3

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.

Answer 2

[Mitch Lautigar]

riskUserId=[];

%MATLAB is expecting a 1 or 0 for preexisting conditions. IF the values in the table are true/false, use strcmpi(). This would look like (strcmpi(data.Preexisting_Conditions,"true"))

if (data.Age>60) || (data.Preexisting_Conditions==1)

riskUserId= [riskUserId;data.User_ID]; %Stack all values into an array for easy viewing.

end

[Mehdi Jaiem]

The content of the column Preexisting_Conditions is already boolean:

Name First Name User_ID Contact_ID Infection Preexisting_Conditions Age

____________ ______________ __________ ____________ _________ ______________________

{'Maier' } {'Alfred' } 1e+05 {1×5 double} true false 70

{'Schulz' } {'Petra' } 1e+05 {[ 100017]} false false 64

{'Schmidt' } {'Dieter' } 1e+05 {1×2 double} false false 58

{'Meier' } {'Benjamin' } 1e+05 {[ 100012]} false false 52

{'Gross' } {'Michael' } 1.0001e+05 {1×5 double} true false 46

{'Klein' } {'Nadja' } 1.0001e+05 {1×2 double} false false 40

I tried using strcmp but it only gives me zeros and ones instead of true and false. Instead I used the followwing line.

data.Preexisting_Conditions=categorical(data.Preexisting_Conditions)=='yes';

(originally I had 'yes' and 'no' instead of 'true' and 'false')

Now the columns Preexisting_Conditions and Infection are of type

class(data.Preexisting_Conditions)

ans =

'logical'