Selecting values in an array

if I have an structure called results with arrays 'position' and 'profit', how can I build an array when, at the same time, position = 1 and profit = a positive double value. How about when profit = a negative value?

results = 
position: [368x1 double]
profit: [368x1 double]

sample data:

x = [results.position, results.profit]
x = 
  -1           0
  -1         12.265
   1           0
   1        -10.01
   1         10.11

Thank you for your help.

Answer 1

[Geoff]

Logical indexing:

xfiltered = x( x(:,1)==1 & x(:,2)>0, : );

I'm sure you can work out the variations on this.

You can use 'OR' instead of 'AND' by replacing & with |.

Answer 2

[Image Analyst]

Try this:

% Create sample data.
results.position = [-1 -1 1 1 1]';
results.profit = [0 12.265 0 -10.01 10.11]';
% Show all the data.
x = [results.position, results.profit]

% Create logical indexes for the various requested criteria.
positivePositionIndexes = results.position > 0
positiveProfitIndexes = results.profit > 0
negativeProfitIndexes = results.profit < 0

% Now create the output array for the two scenarios.

% Case 1: both position and profit must be positive.
case1Indexes = positivePositionIndexes & positiveProfitIndexes;
case1 = [results.position(case1Indexes), results.profit(case1Indexes)]

% Case 2: position must be positive and profit must be negative.
case2Indexes = positivePositionIndexes & negativeProfitIndexes;
case2 = [results.position(case1Indexes), results.profit(case2Indexes)]

In the command window:

case1 =
    1.0000   10.1100
case2 =
    1.0000  -10.0100