search character in table

symbol ={'R0';'R1';'R2';'R3';'R4';'R5';'R6';'R7';'R8';'R9';'R10';'R11';'R12';'R13';'R14';'R15';'SCREEN';'KBD';'SP';'LCL';'ARG';'THIS';'THAT'};

Address={'0';'1';'2';'3';'4';'5';'6';'7';'8';'9';'10';'11';'12';'13';'14';'15';'16384';'24576';'0';'1';'2';'3';'4'};

symboltable=table(symbol,Address);

k6 = isfield(symboltable.symbol,trim_Ainstruction)

where 'trim_Ainstruction' is a char ..and we are assigning trim_Ainstruction as screen(in char data type)

while am trying to search 'screen' in table 'symboltable' using above code, its returns zero eventhough the specific string is in the table. can anyone help me?

Answer 1

[Cris LaPierre]

You are not using isfield correctly. This function is for searching structure array fieldnames, not character vectors.

Consider looking into strcmp or ismember. For example

symbol ={'R0';'R1';'R2';'R3';'R4';'R5';'R6';'R7';'R8';'R9';'R10';'R11';'R12';'R13';'R14';'R15';'SCREEN';'KBD';'SP';'LCL';'ARG';'THIS';'THAT'};
Address={'0';'1';'2';'3';'4';'5';'6';'7';'8';'9';'10';'11';'12';'13';'14';'15';'16384';'24576';'0';'1';'2';'3';'4'};
symboltable=table(symbol,Address);

ismember('R6',symboltable.symbol)

ans = logical
   1

[Stephen23]

It is very odd that ISFIELD does not throw an error for data types that do not have fields:

isfield({},'a')

ans = logical
   0

isfield([],'a')

ans = logical
   0

I would not have expected that... a descriptive error message would be more useful, IMHO.

[Cris LaPierre]

Suggestions welcomed

[VISHNU DIVAKARAN PILLAI]

so can we use that result for if condition, i think it wil show an error.i need to use the result for if condition.

[VISHNU DIVAKARAN PILLAI]

ismember is working but its showing as array.. i need to use the result for if condition.. can u pls suggst?

[Cris LaPierre]

Yes, logical results can be used for your if condition. That's new information that was not in the original question. What is the condition you want to have?

symbol ={'R0';'R1';'R2';'R3';'R4';'R5';'R6';'R7';'R8';'R9';'R10';'R11';'R12';'R13';'R14';'R15';'SCREEN';'KBD';'SP';'LCL';'ARG';'THIS';'THAT'};
Address={'0';'1';'2';'3';'4';'5';'6';'7';'8';'9';'10';'11';'12';'13';'14';'15';'16384';'24576';'0';'1';'2';'3';'4'};
symboltable=table(symbol,Address);

isfound = ismember('R6',symboltable.symbol);

if isfound
    disp('Value found in symbol')
end

Value found in symbol

As you can see if the example above, the code you have provided here returns a single value. Share the code you are running.