Convert seconds to compound duration: Difference between revisions

</pre>

=={{header|Erlang}}==

{{trans|Haskell}}

Function ''mapaccumr/3'' is adapted from [http://lpaste.net/edit/47875 here].

Function ''intercalate/2'' is copied from [https://github.com/tim/erlang-oauth/blob/master/src/oauth.erl a Tim Fletcher's GitHub repository].

<lang erlang>

%% @author Salvador Tamarit <tamarit27@gmail.com>

-module(convert_seconds).

-export([test/0]).

test() ->

lists:map(fun convert/1, [7259, 86400, 6000000]),

ok.

convert(Seconds) ->

io:format(

"~7s seconds = ~s\n",

[integer_to_list(Seconds), compoundDuration(Seconds)] ).

% Compound duration of t seconds. The argument is assumed to be positive.

compoundDuration(Seconds) ->

intercalate(

", ",

lists:map(

fun({D,L}) -> io_lib:format("~p ~s",[D, L]) end,

compdurs(Seconds) ) ).

% Time broken down into non-zero durations and their labels.

compdurs(T) ->

Ds =

reduceBy(

T,

lists:map(

fun(Dl) -> element(1,Dl) end,

tl(durLabs()) ) ),

lists:filter(

fun(Dl) -> element(1,Dl) /= 0 end,

lists:zip(

Ds,

lists:map(

fun(Dl) -> element(2,Dl) end,

durLabs() ) ) ).

% Duration/label pairs.

durLabs() ->

[

{undefined, "wk"},

{7, "d"},

{24, "hr"},

{60, "min"},

{60, "sec"}

].

reduceBy(N, Xs) ->

{N_, Ys} = mapaccumr(fun quotRem/2, N, Xs),

[N_ | Ys].

quotRem(X1, X2) ->

{X1 div X2, X1 rem X2}.

% **************************************************

% Adapted from http://lpaste.net/edit/47875

% **************************************************

mapaccuml(_,I,[]) ->

{I, []};

mapaccuml(F,I,[H|T]) ->

{Accum, NH} = F(I,H),

{FAccum, NT} = mapaccuml(F,Accum,T),

{FAccum, [NH | NT]}.

mapaccumr(_,I,[]) ->

{I, []};

mapaccumr(F,I,L) ->

mapaccuml(F,I,lists:reverse(L)).

% **************************************************

% **************************************************

% Copied from https://github.com/tim/erlang-oauth/blob/master/src/oauth.erl

% **************************************************

intercalate(Sep, Xs) ->

lists:concat(intersperse(Sep, Xs)).

intersperse(_, []) ->

[];

intersperse(_, [X]) ->

[X];

intersperse(Sep, [X | Xs]) ->

[X, Sep | intersperse(Sep, Xs)].

% **************************************************

</lang>

Output:

<pre>

7259 seconds = 59 d, 2 min

86400 seconds = 1 sec

6000000 seconds = 9 wk, 40 hr, 10 min, 6 sec