[erlang-questions] List comprehensions assistance

[Hugo Mills]

On Mon, Aug 17, 2015 at 10:40:35PM +0000, Technion wrote:
> Hi,
> 
> 
> I have the following piece of code, which works correctly:
> 
> 
>    ConvertFun = fun({X, Y}) -> {[{<<"address">>,
>             list_to_binary(inet:ntoa(X))}, {<<"stat">>, Y}]} end,
>     ScanConverted = lists:map(ConvertFun, Results),
> 
> 
> The reason for this very specific mapping is to convert it into exactly the format jiffy expects (in order to generate the correct JSON). I've been experimenting with rewriting this as a list comprehension (largely as a learning exercise).
> 
> 
> Code like this fails to compile:
> 
> 
>     ScanConverted = [[{<<"address">>, list_to_binary(inet:ntoa(X))},
>                   {<<"stat">>, Y}]| {X, Y} <- Results]
> 
> 
> src/ipmangle.erl:31: syntax error before: '<-'
> 
> 
> Any pointers on this would be appreciated.

   A list comprehension is [ Expr || Var <- List ]. You have
[ Expr | Var <- List ].

   Hugo.

PS. Yay! One I can answer! ;)

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Hugo Mills             | I believe that it's closely correlated with the
hugo@REDACTED carfax.org.uk | aeroswine coefficient
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PGP: E2AB1DE4          |                                       Adrian Bridgett
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