Erlang Programming Examples

Updating a Value of the Record

erlang

-module(helloworld). 
-export([start/0]). 
-record(person, {name = "", id}). 

start() -> 
   P = #person{name = "John",id = 1}, 
   P1 = P#person{name = "Dan"}, 
   io:fwrite("~p~n",[P1#person.id]), 
   io:fwrite("~p~n",[P1#person.name]).

Accessing a Value of the Record

erlang

-module(helloworld). 
-export([start/0]). 
-record(person, {name = "", id}). 

start() -> 
   P = #person{name = "John",id = 1}, 
   io:fwrite("~p~n",[P#person.id]), 
   io:fwrite("~p~n",[P#person.name]).

Erlang tuple_to_list

erlang

-module(helloworld). 
-export([start/0]). 

start() -> 
   io:fwrite("~w",[tuple_to_list({1,2,3})]).

Erlang list_to_tuple

erlang

-module(helloworld). 
-export([start/0]). 

start() -> 
   io:fwrite("~w",[list_to_tuple([1,2,3])]).

Erlang is_tuple

erlang

-module(helloworld). 
-export([start/0]). 

start() -> 
   P = {john,24,{june,25}} , 
   io:fwrite("~w",[is_tuple(P)]).

Erlang Tuples

erlang

-module(helloworld). 
-export([start/0]). 

start() ->
   P = {john,24,{june,25}} , 
   io:fwrite("~w",[tuple_size(P)]).

Erlang Map remove

erlang

-module(helloworld). 
-export([start/0]). 

start() -> 
   Lst1 = [{"a",1},{"b",2},{"c",3}], 
   Map1 = maps:from_list(Lst1), 
   io:fwrite("~p~n",[maps:remove("a",Map1)]).

Erlang Map values

erlang

-module(helloworld). 
-export([start/0]). 

start() ->   
   Lst1 = [{"a",1},{"b",2},{"c",3}], 
   Map1 = maps:from_list(Lst1), 
   io:fwrite("~p~n",[maps:values(Map1)]).

Erlang Map put

erlang

-module(helloworld). 
-export([start/0]). 

start() -> 
   Lst1 = [{"a",1},{"b",2},{"c",3}], 
   Map1 = maps:from_list(Lst1), 
   io:fwrite("~p~n",[maps:put("d",4,Map1)]).

Erlang Map merge

erlang

-module(helloworld). 
-export([start/0]). 

start() ->
   Lst1=[{"a",1},{"b",2},{"c",3}], 
   Lst2=[{"d",4},{"e",5},{"f",6}], 
   Map1 = maps:from_list(Lst1), 
   Map2 = maps:from_list(Lst2), 
   io:fwrite("~p~n",[maps:merge(Map1,Map2)]).

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