Comments on: The Python Lambda

By: Glenbot

Glenbot — Tue, 27 Jul 2010 07:59:50 +0000

Good post. I wish lambda was as flexible as anonymous functions in JavaScript. One great use of lambda in Django is in the permission_required decorator.

By: Ryan

Ryan — Wed, 21 Jul 2010 05:41:22 +0000

Good read, you might want to take a look at my post as well: http://blog.ryanbalfanz.net/?p=235

By: driscollis

driscollis — Tue, 20 Jul 2010 20:36:33 +0000

I almost mentioned that, but thought it might make the article rather confusing.

- Mike

By: vvl

vvl — Tue, 20 Jul 2010 18:14:45 +0000

Not to forget lambda's use in functional programming, e.g. having a function return another function:

def make_incrementor(n): return lambda(x): x + n

which produces a function that increments its argument by n. Not the most usual application but some things can be done very beautifully with this.

By: Dougal Matthews

Dougal Matthews — Tue, 20 Jul 2010 17:59:06 +0000

Very true – they are also faster. Perhaps not the best example but I couldn't think of another one off the top of my head

By: driscollis

driscollis — Tue, 20 Jul 2010 17:58:13 +0000

Rob,

Thanks for the feedback! I think lambda tends to be antithetical to the normal Python philosophy as well.

- Mike

By: driscollis

driscollis — Tue, 20 Jul 2010 17:56:34 +0000

Hi Dougal,

I don't know how I missed that one. Thanks for the heads-up!

- Mike

By: Rob Weir

Rob Weir — Tue, 20 Jul 2010 15:45:25 +0000

Don't forget operator.itemgetter/attrgetter – for many simple key functions, they are imho clearer than a lambda.

By: Dougal Matthews

Dougal Matthews — Tue, 20 Jul 2010 13:11:21 +0000

A nice example of the lambda statement is the python sorted() built in where you can provide a lambda to sort an itteratable.

For example, to sort a list of objects with the property last_name

sorted(list, key=lambda i: i.last_name)