An easy way to perform an if in lambda is by using list comprehension. You can't raise an exception in lambda, but this is a way in Python 3.x to do something close to your example:

I saw some examples using built-in functions like sorted, sum etc. that use key=lambda. What does lambda mean here? How does it work? For the general computer science concept of a lambda, see …

by_attribute = lambda x: x.attribute == value xs = filter(by_attribute , xs) Yes, that's two lines of code instead of one, but you clean filter expression from cumbersome lambda and by naming lambda …

I don't quite understand the syntax behind the sorted() argument: key=lambda variable: variable[0] Isn't lambda arbitrary? Why is variable stated twice in what looks like a dict?

The closure of a lambda expression is this particular set of symbols defined in the outer context (environment) that give values to the free symbols in this expression, making them non-free …

Lambda functions are most useful in things like callback functions, or places in which you need a throwaway function. JAB's example is perfect - It would be better accompanied by the keyword …

Feb 17, 2016 · Firstly, Lambda functions do not listen for traffic on any port and so the concept of inbound traffic to a Lambda function is not applicable. Secondly, outbound connections from the …

Jul 10, 2015 · The Lambda function expects JSON input, therefore parsing the query string is needed. The solution is to change the query string to JSON using the Mapping Template.

Mar 30, 2014 · lambda *args: None With some minor differences in that one is a lambda and one isn't. (For example, __name__ will be do_nothing on the function, and <lambda> on the lambda.) Don't …

May 31, 2013 · 1 (lambda x: x%2) is a function, and dividing a function by 2 doesn't make any sense. You probably want to call it and divide what the value it returned.