CODEWITHSUNDEEP
stringerlangerl
channa ly
channa ly

Reputation: 9927

string value in erlang

I am a newbie in erlang. I have to maintain and implement new feature of an an backend project built in erlang. I have strong background in c/c++, php, ruby, python and javascript. I have had problem in implementing a feature to remove some of the prefixes from list of phone number

-module(reminder_group).
-export([address_with_no_prefix/1]).

-define(PREFIXES, [
    '855', 
    '+855', 
    '0', 
    '+0', 
    '+'
 ]).

address_with_no_prefix(Address) ->
  address_with_no_prefix(Address, ?PREFIXES).

address_with_no_prefix(Address, []) -> Address;

address_with_no_prefix(Address, Prefixes) ->
  [Prefix|H] =  Prefixes,
  Length = string:len(Prefix),
  AddressPrefix = string:substr(Address, 1, Length),

  if 
   Prefix == AddressPrefix -> 
     string:substr(Address, Length);
   true ->  
     address_with_no_prefix(Address, H)
end.

After compiling I run 

reminder_group:address_with_no_prefix("0123445")

I got the following error:

1> reminder_group:address_with_no_prefix("0123445").
 ** exception error: bad argument
    in function  length/1
    called as length('855')
    in call from string:len/1 (string.erl, line 66)
    in call from reminder_group:address_with_no_prefix/2 (src/models/reminder_group.erl, line 34)

It seems like problem of Length = string:len(Prefix) however I test to run

string:len("855").

it works fine with the result of 3. Is there anything wrong with my list of string value ? Please help.

Upvotes: 3

Views: 173

Answers (1)

Gian
Gian

Reputation: 13945

You're using single quotes (rather than double quotes) to denote your prefixes. I assume you meant for these to be strings, not atoms (hence applying string:len)?

Your test worked because you correctly used double quotes to construct a string literal.

Upvotes: 3

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