[erlang-questions] Lists Comprehension issue?

[German Vidal]

Hi, L should be a list of lists, e.g., append([[1,2],[3,4]]) will return [1,2,3,4].
g--

On 14 Jan 2015, at 09:06, Carlos Suarez Fontalvo <eng.carlos.suarez@REDACTED> wrote:

> Hi. I've reading this documentation: http://www.erlang.org/doc/programming_examples/list_comprehensions.html
> 
> And it says that
> 
> 3.5  Simplifications with List Comprehensions
> 
> As an example, list comprehensions can be used to simplify some of the functions in lists.erl:
> 
> append(L)   ->  [X || L1 <- L, X <- L1].
> map(Fun, L) -> [Fun(X) || X <- L].
> filter(Pred, L) -> [X || X <- L, Pred(X)].
> 
> 
> However when I tried to test this first example "append" doing something simple like this:
> 
> 73> [X || L1 <- 20, X <- L1].
> ** exception error: bad generator 20
> 
> I got a "exception error" message. Any idea why?. Am I not considering something?
> 
> Thanks in advance
> 
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