Re: How to print lambda result ?

[Tino Wildenhain]

Barak, Ron wrote:

Thanks Tino: your solutions without the lambda work nicely.
What I still don't understand is why the print does not execute the lambda and 
prints the result, instead of printing the lambda's object description.
Bye,
Ron.

__str__() returning __repr__() which is at its default)

Regards
Tino

Well its up to the implemention what a class is supposed to return when its __str__() is called. Default is what you see. (this is actually

-----Original Message-----
From: Tino Wildenhain [mailto:t...@wildenhain.de]
Sent: Tuesday, January 20, 2009 14:22
To: Barak, Ron
Cc: python-list@python.org
Subject: Re: How to print lambda result ?

Hi,

Barak, Ron wrote:

Hi,

Wanting to print the correct plural after numbers, I did the following:

for num in range(1,4):
    string_ = "%d event%s" % (num,lambda num: num > 1 and "s" or "")
    print string_

However, instead of getting the expected output:

1 event
2 events
3 events

I get:

1 event<function <lambda> at 0x00AFE670>
2 event<function <lambda> at 0x00AFE670>
3 event<function <lambda> at 0x00AFE6B0>

lambda creates a function so this is the result you are seeing. You would need 
to call the function to get your result.

(num,(lambda n: n >1 and "s" or "")(num))

which is just a quite useless application of lambda :-)

(num,num >1 and "s" or "")

or even

(num,"s" if num >1 else "")

in python > 2.5

or in python <3.0:

(num,"s"*(num >1))

:-)

HTH
Tino

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