def substitute(search, replace, text)

  text.gsub(search, replace)

end

text = "Hello World, this is a sample text."

search = "sample"

replace = "example"

puts substitute(search, replace, text)

# Output: "Hello World, this is a example text."

def replace_keys_with_values(hash, text)

  hash.each do |key, value|

    text.gsub!(key, value)

  end

  text

end

replace_keys_with_values({ "key1" => "value1", "key2" => "value2" }, "key1 and key2")

# returns "value1 and value2"

 

 

In this example, the substitute method uses the gsub method, which stands for "global substitution", to replace all occurrences of the search string in the text input with the replace string. The gsub method returns a new string with the replacements, and this new string is then returned by the substitute method.

How to troubleshoot nil exceptions in Ruby on Rails codebase?

Troubleshooting nil exceptions in a Ruby on Rails codebase can be a challenging task, but there are several strategies that can help you to find and fix the problem:

1. Use a debugger: A debugger is a powerful tool that allows you to step through the code line by line and inspect the state of the variables at each step. This can help you to identify the line of code that is causing the exception and the variable that is returning nil.

2. Check the stack trace: The stack trace is a list of the method calls that led to the exception. It can help you to identify the method that is causing the exception and the arguments that were passed to it.

3. Check the logs: The Rails logs can provide more information about the exception and can help you to identify the request that caused the exception.

4. Use a linter or static analysis tool: There are several linters and static analysis tools that can be used in a Ruby on Rails project, such as RuboCop, Brakeman, and Reek. These tools can help you to find potential issues and vulnerabilities in your codebase.

5. Use the byebug gem: byebug is a powerful gem that provides an interactive debugger for Ruby. It can be used to check the state of the variables and navigate through the code.

6. Use the binding.pry gem: pry is a powerful gem that provides an interactive shell for Ruby. It can be used to check the state of the variables and navigate through the code.

7. Test your code: By writing tests and running them you can ensure that the code is working correctly and the test will catch any exception in the future.

8. Check the documentation and the source code: Sometimes the exception is caused by a bug in a gem or a library that you are using. Check the documentation and the source code of the gem or library to see if there is a fix or a workaround.

It's important to note that these are just some of the strategies that can be used to troubleshoot nil exceptions in a Ruby on Rails codebase and the approach that you choose will depend on the specific circumstances of the exception.