Data commit

Task/CSV-data-manipulation/Erlang/csv-data-manipulation.erl

@@ -0,0 +1,36 @@
+-module( csv_data ).
+
+-export( [change/2, from_binary/1, from_file/1, into_file/2, task/0] ).
+
+change( CSV, Changes ) -> lists:foldl( fun change_foldl/2, CSV, Changes ).
+
+from_binary( Binary ) ->
+        Lines = binary:split( Binary, <<"\n">>, [global] ),
+        [binary:split(X, <<",">>, [global]) || X <- Lines].
+
+from_file( Name ) ->
+        {ok, Binary} = file:read_file( Name ),
+        from_binary( Binary ).
+
+into_file( Name, CSV ) ->
+        Binaries = join_binaries( [join_binaries(X, <<",">>) || X <- CSV], <<"\n">> ),
+        file:write_file( Name, Binaries ).
+
+task() ->
+       CSV = from_file( "CSV_file.in" ),
+       New_CSV = change( CSV, [{2,3,<<"23">>}, {4,4,<<"44">>}] ),
+       into_file( "CSV_file.out", New_CSV ).
+
+
+
+change_foldl( {Row_number, Column_number, New}, Acc ) ->
+        {Row_befores, [Row_columns | Row_afters]} = split( Row_number, Acc ),
+        {Column_befores, [_Old | Column_afters]} = split( Column_number, Row_columns ),
+        Row_befores ++ [Column_befores ++ [New | Column_afters]] ++ Row_afters.
+
+join_binaries( Binaries, Binary ) ->
+        [_Last | Rest] = lists:reverse( lists:flatten([[X, Binary] || X <- Binaries]) ),
+        lists:reverse( Rest ).
+
+split( 1, List ) -> {[], List};
+split( N, List ) -> lists:split( N - 1, List ).