How to remove the new line characters from a string?

Question

I want to remove all the newline symbols:

aaa = """
fdsfds fdsfds
  fdsfdsfds
fdsfdsfds
""" |> String.strip("\r\n")

And I get:

argument error

What's wrong with this?

Solution 1

What's wrong with this?

String.strip only supports removing one character. That error is thrown as Elixir tries to convert "\r\n" to a single character (source):

iex(1)> s = "\r\n"
"\r\n"
iex(2)> <<s::utf8>>
** (ArgumentError) argument error

Moreover, String.strip has been deprecated in favor of String.trim, which does support a string as the second argument, but that function will only remove the exact sequence \r\n from the starting and ending of the string:

iex(1)> aaa = """
...(1)> fdsfds fdsfds
...(1)>   fdsfdsfds
...(1)> fdsfdsfds
...(1)> """
"fdsfds fdsfds\n  fdsfdsfds\nfdsfdsfds\n"
iex(2)> String.trim(aaa, "\r\n")
"fdsfds fdsfds\n  fdsfdsfds\nfdsfdsfds\n"
iex(3)> String.trim(aaa, "\r\n") == aaa
true

which I doubt is what you want as you said "I want to remove all the symbol of a new line". To remove all \r and \n, you can use String.replace twice:

iex(4)> aaa |> String.replace("\r", "") |> String.replace("\n", "")
"fdsfds fdsfds  fdsfdsfdsfdsfdsfds"

Solution 2

Escape the newlines

"""
fdsfds fdsfds \
  fdsfdsfds \
fdsfdsfds
"""

Comments

[Aleksei Matiushkin]

aaa |> String.replace(~r/\r|\n/, "")?

[Dogbert]

@mudasobwa I personally wouldn't use a Regex for such simple cases, but that's certainly a valid solution! I also think in this case my 2 String replace solution would be faster than your Regex one although I haven't measured it.

[Francisco Quintero]

Thanks for the String.trim tip about the exact sequence.

[Mario Uher]

This should be the accepted answer imho.