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Oct 15, 2019 · 150. Starting Python 3.8, and the introduction of assignment expressions (PEP 572) (:= operator), it's now possible to capture the condition value (data.readline()) of the while loop as a variable (line) in order to re-use it within the body of the loop: while line := data.readline(): do_smthg(line)
Since Python 3.8, code can use the so-called "walrus" operator (:=), documented in PEP 572, for assignment expressions. This seems like a really substantial new feature, since it allows this form of assignment within comprehensions and lambdas. What exactly are the syntax, semantics, and grammar specifications of assignment expressions?
Jul 10, 2018 · 1. I know I can use assignment operators with arithmetic operators in Python, for example: x = 0x8. x |= 0x1 # x equals 9. I'd like to know if this is also possible with logical operators, for example something like: x = 2 > 3 # False. y = 4 > 3 # True. x or= y # x equals True.
C and many other languages have a conditional (AKA ternary) operator. This allows you to make very terse choices between two values based on the truth of a condition, which makes expressions, including assignments, very concise. I miss this because I find that my code has lots of conditional assignments that take four lines in Python: Whereas ...
There is conditional assignment in Python 2.5 and later - the syntax is not very obvious hence it's easy to miss. Here's how you do it: x = true_value if condition else false_value For further reference, check out the Python 2.5 docs.
In python and other languages like C, "=" is a assignment operator and is used to assign a value to a variable. Example: a=2 # the value of a is 2. whereas "==" is Comparison operator and is used to check whether 2 expressions give the same value .Equality check returns true if it succeeds and else return false. Example: a=2 b=3 c=2.
There is no analogue of int() here, since operators are keywords in the language and not values. Once you've compared that input string to your list of operands and determined the operator that it corresponds to, you can use the Python standard library's operator module to calculate the result of applying the operator to your two operands.
Sep 28, 2009 · Python is not C or C++. Different design decisions went into making the language. In particular, Python deliberately does not define assignment operators that can be used in an arbitrary expression; rather, there are assignment statements and augmented assignment statements. See reference below. –
Apr 8, 2010 · PEP 572 seeks to add assignment expressions (or "inline assignments") to the language, but it has seen a prolonged discussion over multiple huge threads on the python-dev mailing list—even after multiple rounds on python-ideas. Those threads were often contentious and were clearly voluminous to the point where many probably just tuned them out.
Oct 15, 2012 · Assignment to a bare name in Python (name = ...) is a different operation than assignment to anything else. In particular it is different from item assignment (name[0] = ...) and attribute assignment (name.attr = ...). They all use the equal sign, but the latter two are manipulable with hooks (__setitem__ and __setattr__), can call arbitrary ...
