Python - Pass a variable to lambda if it exists

Question

I'm curious about how to make code more efficient in Python, I've got to execute an action, which may or may not have a payload attached depending on the length of a list.

Right now, I'm using an if statement to determine if there is a payload. Is there a better or cleaner way to find this?

                    #If payload, execute action with it
                    if(len(data) > 1):
                        action= mec.action(data[1])
                    #If no payload, then just execute action
                    else:
                        action= mec.action()
                    return action

ideally cleaner code / better logic. I don't think it's possible to make this more efficient in terms of time? — ForeverLearning
– ForeverLearning, Commented Aug 14, 2016 at 1:47
It looks fine as it is: if you remove the comments, the code is still understandable. The only things I'd change is the if statement: you don't need those parentheses. — user824425
– user824425, Commented Aug 14, 2016 at 1:49

dunck · Accepted Answer · 2016-08-14 01:45:38Z

3

The code is efficient as is - instead of optimising for efficiency, try optimising for clarity first. If the code then becomes a performance hotspot... think about looking at the efficiency.

Remembering that a return ends a function; this is a slightly cleaner alternative:

# execute with payload if exists
if(len(data) > 1):
    return mec.action(data[1])
# execute without payload 
# this isn't reached if len(data) > 1
return mec.action()

answered Aug 14, 2016 at 1:45

dunck

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1 Comment

Peter Rowell Over a year ago

"try optimising for clarity first." This is something that can take a long time to learn in software. Clever code is the bane of maintainers, including yourself 6 months from now. Write clean code, profile the performance, then optimize what needs to be optimized ... and comment the crap out of anything even vaguely "clever."

U2EF1 · Accepted Answer · 2016-08-14 01:51:42Z

2

Python comes with vararg syntax you can use for this directly.

return mec.action(*data[1:])

(I'm assuming here that data[2] onwards aren't meaningful, or you could use mec.action(*data[1:2]))

answered Aug 14, 2016 at 1:51

U2EF1

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Comments

Sergio Ayestarán · Accepted Answer · 2017-04-02 03:52:48Z

0

In this case just use a ternary operator like this:

return mec.action(data[1]) if(len(data) > 1) else mec.action()

Hope it helps!

edited Apr 2, 2017 at 3:52

Sergio Ayestarán

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answered Apr 1, 2017 at 11:10

aljgom

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