What does the := operand mean, more specifically for Python?
Can someone explain how to read this snippet of code?
node := root, cost = 0
frontier := priority queue containing node only
explored := empty set
In the context of the question, we are dealing with pseudocode, but starting in Python 3.8, := is actually a valid operator that allows for assignment of variables within expressions:
# Handle a matched regex
if (match := pattern.search(data)) is not None:
# Do something with match
# A loop that can't be trivially rewritten using 2-arg iter()
while chunk := file.read(8192):
process(chunk)
# Reuse a value that's expensive to compute
[y := f(x), y**2, y**3]
# Share a subexpression between a comprehension filter clause and its output
filtered_data = [y for x in data if (y := f(x)) is not None]
See PEP 572 for more details.
What you have found is pseudocode
Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm.
:= is actually the assignment operator. In Python this is simply =.
To translate this pseudocode into Python you would need to know the data structures being referenced, and a bit more of the algorithm implementation.
Some notes about psuedocode:
:= is the assignment operator or = in Python= is the equality operator or == in Python procedure fizzbuzz
For i := 1 to 100 do
set print_number to true;
If i is divisible by 3 then
print "Fizz";
set print_number to false;
If i is divisible by 5 then
print "Buzz";
set print_number to false;
If print_number, print i;
print a newline;
end
void function fizzbuzz
For (i = 1; i <= 100; i++) {
set print_number to true;
If i is divisible by 3
print "Fizz";
set print_number to false;
If i is divisible by 5
print "Buzz";
set print_number to false;
If print_number, print i;
print a newline;
}
Note the differences in brace usage and assignment operator.