Why is exist(variable,'var') not seeing a variable?

17 views (last 30 days)
I have a function to which a variable is passed. The variable exists:
'signedOrNot = signed'
When I call 'exist signedOrNot var' it is found:
ans = 1
But when I use exist(signedOrNot,'var'), as I would in an if statement, it is not:
ans = 0
Any thoughts?

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 24 Sep 2018
exist('signedOrNot','var')

More Answers (1)

Steven Lord
Steven Lord on 24 Sep 2018
This line of code tests whether the variable with the name signedOrNot exists in the workspace.
exist('signedOrNot', 'var')
This line of code tests whether the variable whose name is stored in the variable signedOrNot exists in the workspace.
exist(signedOrNot, 'var')
Compare:
% if a variable by this name exists, choose a different name
signedOrNot = 'thisVariableShouldNotExist';
passingName = exist('signedOrNot', 'var') % true, signedOrNot exists
passingContentsOfVariable = exist(signedOrNot, 'var') % false, thisVariableShouldNotExist doesn't
with:
x = 42;
signedOrNot = 'x';
passingName = exist('signedOrNot', 'var') % true, signedOrNot exists
passingContentsOfVariable = exist(signedOrNot, 'var') % true, x exists

Categories

Find more on Variables in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!