Replacing string codepoints with patterns

In this recipe, we will demonstrate how to replace codepoints in a string using a match pattern. We will use the String.replace/4 function to help with this task.

Note

A codepoint, in this context, is the binary representation of a UTF-8 encoded character.

Getting ready

This recipe will be performed inside an IEx session. Start it by executing the iex command in your command line.

How to do it…

To find a pattern in a string and replace it, follow these steps:

1. Define a string:

   iex(1)> my_string = "[e-mail] [e-mail]"
   "[e-mail] [e-mail]"
   

2. Define a string pattern to use with String.replace:

   iex(2)> my_pattern = "@"
   "@"
   

3. Perform the replacement using the default options:

   iex(3)> String.replace(my_string, my_pattern, "(at)") 
   "user1(at)server.domain user2(at)server.domain"
   

4. Perform the replacement only at the first pattern occurrence:

   iex(4)> String.replace(my_string, my_pattern, "(at)", global: false)
   "user1...