Ruby File Open Block

Ruby block patterns and how to implement file open managing resources with blocks.

Ruby file open block.

Let s learn to do this ourselves. In the case of a file open for writing this is very important and can actually prevent lost data. With no associated block file open is a synonym for new. If the optional code block is given it will be passed the opened file as an argument and the file object will automatically be closed when the block terminates.

How is this done. Open filename mode perm opt file block obj. File openopens a new file if there is no associated block. With no associated block file open is a synonym for new.

If the optional code block is given it will be passed the opened file as an argument and the file object will automatically be closed when the block terminates. File file open yourfilename txt. If the optional block is given it will be passed file as an argument and the file will automatically be closed when the block terminates. You can open the file in any of the modes when using the method sysread.

For example following is the input text file this is a simple text file for testing purpose. Blocks are an excellent way to abstract pre and post processing. The syntax to open an existing file using ruby is as follows. The value of the block will be returned from file open.

This method is similar to the file new method which is used to create a file object the only difference between the two being that the file open method can be associated with a block unlike the file new method. A wonderful example is.