ternary operator in matlab

Question

is there a way of typing for if like:

var = (cond) ? true : false;

or do we have to use this format?

if (cond)
 true
else
 false
end

Solution 1

MatLab doesn't have a ternary operator, or any other syntactic sugar for one-line if-statements. But if your if-statement is really simple, you could just write it in one line anyway:

if (cond); casetrue(); else; casefalse(); end

It's not as simple as ternary operator, but still better than writing it in 5 lines of code.

Solution 2

Hmm... no one has mentioned this

fi = @(varargin)varargin{end-varargin{1}}

somewhere in the docs it is written the `end' is coming to one so this will be more future proof

fi = @(varargin)varargin{length(varargin)-varargin{1}}

Usage :

fi(input('Do you like Matlab ? '),'yes','no')
>> no

If your in the need of inline cases see Mathworks ...

Solution 3

If you only need true or false, you can do what MatlabSorter suggests. In case you want a real tertiary operator (i.e. a = b ? c : d), there is none in MATLAB. However, using the file supplied here, you can get close.

Solution 4

You can do

var = 5 > 4;

which will set var to true. Just substitute what ever you need for 5 > 4.

Solution 5

MATLAB doesn't have conditional expressions, but in some situations you can get a similar effect by saying, e.g., var = cond*true_expr + (1-cond)*false_expr. Unlike C's conditional expression, this will of course always evaluate both true_expr and false_expr, and if cond happens not to be either 0 or 1 (note: false behaves like 0; true behaves like 1) you'll get crazy results.

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Comments

[glglgl]

It should be possible to create a function which takes a condition and two function handles. Then you have the wanted shortcut behaviour.

[Karl]

Na, you can use (a > b) as a factor and then add another product with the opposite statement : var = (a < 0) * (-a) + (a >= 0) * (a)

[Naveen]

If we need to use the ternary operator inside disp or fprintf?

[BlackDog]

Elegant but works only for numerical expressions, I tried it with strings and it returned them as an ASCII values array

[Eric]

This also does not work if true_expr or false_expr are inf

[Juergen S.]

Note: a and b are both evaluated. This may be a difference to if ... else ... end.

[hyiltiz]

Hoever simple, if/switch/loop statements aren't supported in lambda/anonymous function definitions in Matlab.

[tommsch]

For which Matlab version is this? I have R2018a and the assignment var=true_val does not work. Matlab reports a syntax error.

[Jiří]

beware that this does not work if you need lazy evaluation, e.g. b always evaluates regardless of cond (might seem obvious, but you probably just think abstract: 'Ah ternary operator here we go' and use it as normal, things might break for you)...