how to get char index in string with Elixir ?

[fx]

I wan to find char index in string , and I found Erlang have function 

    chr(String, Character) -> Index

I try call chr function in Elixir 

iex(18)> a = "abc"

"abc"

iex(19)> :string.chr(a, "b")

** (FunctionClauseError) no function clause matching in :string.chr/2

    (stdlib) string.erl:96: :string.chr("abc", "b")

iex(19)> :string.chr(a, ?b) 

** (FunctionClauseError) no function clause matching in :string.chr/3

    (stdlib) string.erl:98: :string.chr("abc", 98, 1)

iex(19)> 

 

my question is how to represent a Character in ELixir ? or Have any function like erlang chr in ELixir ?

[Eduardo Gurgel]

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There are some concepts here:

Notice the double/single quotes

Strings = 'I am a erlang string'

Erlang binaries = "I am a erlang binary"

A char is represented using ?, In your case:

iex> :string.chr('abc', ?b)

2

Any library on Erlang will run on Elixir. The error you had happened just because of the data types you passed.

More information on the basic data types: http://elixir-lang.org/getting_started/2.html

Regards,

Eduardo

[Eduardo Gurgel]

In time: also take a look this chapter too: http://elixir-lang.org/getting_started/6.html

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Eduardo

[Eric Meadows-Jönsson]

Use `:binary.match` to find the index of a character in a string. `:binary.match("string", "t")` returns `{3, 1}`, 3 being the index and 1 being the length of the match. Keep in mind that it doesn't return the Nth character, only the Nth byte, characters may span multiple bytes.

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Eric Meadows-Jönsson