Assignment within expression in Python

Question

In Java, if I want to increase a variable A, and set B equal to C, I can do it one statement as follows:

B = C + A - A++;

Python, unfortunately, does not support assignment within literals. What is the best way to mimic this kind of behavior within the language of Python? (with the intention of writing code in as few statements as possible)

Let me set something straight: I am not interested in writing code that is readable. I am interested in writing code with as few statements as possible.

One trivial example of one case where this would work would be to write a class that holds an int and has methods such as plus_equals, increment, etc.

Python is not interested in helping you write code that isn't readable. — Charles Duffy, Jan 13 '16 at 19:05
http://stackoverflow.com/questions/3654830/why-are-there-no-and-operators-in-python — Vahid Msm, Jan 13 '16 at 19:13
*"Python, unfortunately, does not support assignment within literals"* - huh? Nothing in your example Java code is a literal. — Mark Amery, Jul 28 '16 at 20:01

score 4 · Accepted Answer · answered Jan 13 '16 at 19:10

4

In the global namespace, you can do something really ugly like this:

B = globals().__setitem__('A', A + 1) or C

Unfortunately for you (and probably fortunately for the person who has to read the code after you've written it), there is no analogous way to do this with a local variable A.

answered Jan 13 '16 at 19:10

mgilson

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I hope you use this power [responsibly](http://preshing.com/20110926/high-resolution-mandelbrot-in-obfuscated-python/) . . . – mgilson Jan 13 '16 at 19:16
I absolutely love this solution. Thank you – Will Sherwood Jan 13 '16 at 19:17
Gross. Please don't do this – Chad S. Jan 13 '16 at 19:40
@ChadS. -- I completely agree that this code should never be used except for novel experiments like the mandelbrot set code that I linked or code-golf-like competitions where the normal "rules" don't apply ... – mgilson Jan 13 '16 at 20:00

user2357112 · Answer 2 · 2016-07-28T17:17:50.137

-1

Let me set something straight: I am not interested in writing code that is readable. I am interested in writing code with as few statements as possible.

Well, if that's your goal, wrap your entire program in a giant exec:

exec """
<your program here>
"""

Bam, one statement.

edited Jul 28 '16 at 17:17

answered Jan 13 '16 at 19:05

user2357112

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Assignment within expression in Python

2 Answers2