Oct 24, 2011 · If one line code is definitely going to happen for you, Python 3.8 introduces assignment expressions affectionately known as “the walrus operator”. someBoolValue and (num := 20) The 20 will be assigned to num if the first boolean expression is True .

Everybody knows that in Python assignments do not return a value, presumably to avoid assignments on if statements when usually just a comparison is intended: >>> if a = b: File "<st...

Apr 8, 2010 · Note that in Python, unlike C, assignment cannot occur inside expressions. C programmers may grumble about this, but it avoids a common class of problems encountered in C programs: typing = in an expression when == was intended.

Apr 27, 2019 · The one liner doesn't work because, in Python, assignment (fruit = isBig(y)) is a statement, not an expression. In C, C++, Perl, and countless other languages it is an expression, and you can put it in an if or a while or whatever you like, but not in Python, because the creators of Python thought that this was too easily misused (or abused) to ...

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?

May 6, 2015 · For Python 3.8+, PEP 572 introduces Assignment Expressions This allows assigning to variables within an expression using the notation NAME := expr . It can be used within if statements, for example:

Aug 22, 2015 · All target_list productions (i.e. things that look like foo =) in an assignment statement get assigned, from left to right, to the expression_list on the right end of the statement, after the expression_list gets evaluated. And of course the usual 'tuple-unpacking' assignment syntax works within this syntax, letting you do things like

The statement x = y = z to assign the same value to multiple targets (or rather, multiple target-lists, since unpacking is also permitted) was already supported (e.g. since version 1) but is implemented as a special syntax rather than by chaining successive assignment sub-expressions.

May 22, 2020 · A statement is code that tells the computer to do something. A statement has to be written by itself on a line. Examples are assignments, def to define functions, and while to start a loop. An expression is code that calculates a value, and can be used as part of another statement or expression.

Oct 15, 2019 · 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 …