erlang_one_liners.md

10 Erlang one liners to impress your friends

1. Multiple Each Item in a List by 2:

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[X * 2 || X <- lists:seq(1, 11)].

2. Sum a List of Numbers:

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lists:sum(lists:seq(1, 1001)).

3.Verify if Exists in a String:

Wordslist = ["scala", "akka", "play framework", "sbt", "typesafe"].
Tweet = "This is an example tweet talking about scala and sbt".
[lists:member(S, Wordslist) || S <- string:tokens(Tweet, " ")]. 

4. Read in a File:

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file:read_file("ten_one_liners.erl").

5. Happy Birthday to You:

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["Happy Birthday " ++ case X of 2 -> "dear Robert"; _ -> "You" end || X <- lists:seq(1, 4)].

6. Filter list of nubmers:

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[X || X <- lists:seq(40, 60), X >= 50].

7. Fetch and Parse an XML web service:

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inets:start().
xmerl_scan:string(element(3, element(2, httpc:request("http://search.twitter.com/search.atom?&q=erlang")))).

8. Find minimum (or maximum) in a List

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lists:min(lists:seq(1, 10)).
lists:max(lists:seq(1, 10)).

9. Parralel Processing

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[spawn(fun() -> io:format("~w~n", [X * 2]) end) || X <- lists:seq(1, 10)]. 

10. Sieve of Eratosthenes

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N = 50.
[X || X <- lists:usort(lists:seq(2, N + 1)), not lists:member(X, lists:usort([(P * F) || P <- lists:seq(2, round(math:pow(N, 0.5)) + 2), F <- lists:seq(2, round(N / P))]))].