Assignment operators

As you’ve already seen, you can assign values using the = operator.To assign only if the assigned-to variable is null,use the ??= operator.

1. // Assign value to a
2. a = value;
3. // Assign value to b if b is null; otherwise, b stays the same
4. b ??= value;

Compound assignment operators such as += combinean operation with an assignment.

= –= /= %= >>= ^=
+= *= ~/= <<= &= |=

Here’s how compound assignment operators work:

Compound assignment Equivalent expression
For an operator op: a op= b a = a op b
Example: a += b a = a + b

The following example uses assignment and compound assignmentoperators:

1. var a = 2; // Assign using =
2. a *= 3; // Assign and multiply: a = a * 3
3. assert(a == 6);