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In some programming languages, I see (ex.):
x := y What is this := operator generally called and what does it do?
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:= it means "set equal to" An assignment with syntax. v := expr sets the value of variable «v» to the value obtained from expression «expr». Example: X := B Sets the Definition of X to the value of B.
There is new syntax := that assigns values to variables as part of a larger expression. It is affectionately known as “the walrus operator” due to its resemblance to the eyes and tusks of a walrus.
:= is not a valid operator in C. It does however have use in other languages, for example ALGOL 68. Basically, for what you want to know, the := in this example is used to assign the variable PTW32_TRUE to localPty->wNodeptr->spin.
+= Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand. C += A is equivalent to C = C + A.
In all languages that support an operator := it means assignment.
:=, the = operator usually means an equality comparison.= means assignment, == is typically used for equality comparison.does
:=mean=?
I can't recall any languages where := means the same as =.
In MySQL := and = are both used for assignment, however they are not interchangeable and selecting the correct one depends on the context. To make matters more confusing the = operator is also used for comparison. The interpretation of = as either assignment or comparison also depends on context.
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This is a new operator that is coming to Python 3.8 and actually had a role in BDFL Guido van Rossum's early retirement.
Formally, the operator allows what's called an "assignment expression". Informally, the operator is referred to as the "walrus operator".
It allows assignment while also evaluating an expression.
So this:
env_base = os.environ.get("PYTHONUSERBASE", None) if env_base: return env_base can be shortened to:
if env_base := os.environ.get("PYTHONUSERBASE", None): return env_base https://www.python.org/dev/peps/pep-0572/#examples-from-the-python-standard-library
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