rubysyntax's Introduction

Basic syntax for Ruby 💎

There are two methods to open a file in Ruby:

File.new method : Using this method a new file can be created for reading, writing or both. File.open method : Using this method a new file object is created. That file object is assigned to a file. Difference between both the methods is that File.open method can be associated with a block while File.new method can't.

Example

f = File.new("fileName.rb")

Or,

File.open("fileName.rb", "mode") do |f|

Common modes in I/O port

"r": read-only mode is the default mode starts at beginning of file.
"r+": read-write mode, starts at beginning of file.
"w": write-only mode, either creates a new file or overwrites an existing file content.
"w+": read-write mode, either creates a new file or truncates an existing file for reading and writing.
"a": write-only mode, if file exists it will append the file othrwise a new file will be created for writing only.
"a+": read and write mode, if file exists it will append the file othrwise a new file will be created for writing and reading.

Read a file

There are three different methods to read a file.

To return a single line

f.gets
code...

To return the whole file after the current position

f.read
code...

To return file as an array of lines

f.readlines
[code...]

Rename a file

File.rename("olderName.txt", "newName.txt")

Delete a file

File.delete("filename.txt")

Error handling

All exceptions and errors are extensions of the Exception class.

The "begin - rescue"

begin-rescue block is similar to try..catch in JS

begin
  # code may cause error
rescue => e
  # catch error and store it in variable "e"
end

Module

A Module is a collection of methods, constants, and class variables. Modules are defined as a class, but with the module keyword not with class keyword.

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