Question

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Why are there no ||= or &&= operators?

By pure accident I found out today that

 a &= GetBool();

is NOT the same as

 a = a && GetBool();

I must have misunderstood that for years. In the first Example, “GetBool()” is executed even if “a” is false. In the second, it isn’t.

Is there anything to achieve something like “&&=” in C#?

Answer 1

From the documentation:

An expression using the &= assignment operator, such as

x &= y

is equivalent to

x = x & y

except that x is only evaluated once. The & operator performs a
bitwise logical AND operation on integral operands and logical AND on
bool operands.

I would say, to avoid evaluation of y when not necessary, use

x = x && y

and to avoid evaluation of x twice (whatever this means), use

x &= y

You can’t combine both.

Micro-optimized (at least for a theoretical case), it would be:

if (x) x = y;

You don’t need to do anything if x is already false.