Ruby provides powerful and flexible methods for writing data to files. These operations are essential for creating, modifying, and managing file content in your Ruby programs.

Basic File Writing

To write to a file in Ruby, you first need to open it in write mode. The most common method is using File.open with the 'w' mode:


File.open('example.txt', 'w') do |file|
  file.write("Hello, Ruby!")
end

This code creates a new file named 'example.txt' (or overwrites it if it already exists) and writes the string "Hello, Ruby!" to it.

Appending to Files

If you want to add content to an existing file without overwriting its current contents, use the append mode ('a'):


File.open('example.txt', 'a') do |file|
  file.puts("This line will be appended.")
end

The puts method adds a newline character at the end of the string, unlike write.

Writing Multiple Lines

You can write multiple lines to a file using various methods:


File.open('multiline.txt', 'w') do |file|
  file.puts("Line 1")
  file.puts("Line 2")
  file.write("Line 3\n")
  file.write("Line 4\n")
end

Using File.write

For simple write operations, Ruby offers a convenient File.write method:


File.write('quick.txt', 'This is a quick way to write to a file.')

This method creates the file if it doesn't exist or overwrites it if it does.

Important Considerations

Always close files after writing to ensure data is properly saved and resources are released.
Use exception handling to manage potential errors during file operations.
Be cautious when using write mode ('w') as it overwrites existing files.
Consider using Ruby File Modes to control read/write permissions.

File Encoding

When dealing with non-ASCII characters, specify the file encoding:


File.open('unicode.txt', 'w:UTF-8') do |file|
  file.write("こんにちは、ルビー！")
end

This ensures proper handling of Unicode characters in your files.

Related Concepts

To further enhance your understanding of Ruby file operations, explore these related topics:

Mastering file write operations in Ruby opens up possibilities for data persistence, logging, and file manipulation in your applications.