Ruby File Open Block

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.

Ruby file open block.

Always close a file that you open. You can open the file in any of the modes when using the method sysread. Open filename mode perm opt file block obj. With no associated block file open is a synonym for new.

A wonderful example is. For example following is the input text file this is a simple text file for testing purpose. 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. The syntax to open an existing file using ruby is as follows.

Blocks are an excellent way to abstract pre and post processing. Ruby block patterns and how to implement file open managing resources with blocks. Now let s try to read this file usr bin ruby afile file new input txt r if afile content afile sysread 20 puts content else puts unable to open file. How is this done.

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. The value of the block will be returned from file open. In the case of a file open for writing this is very important and can actually prevent lost data. 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.

With no associated block file open is a synonym for new. File openopens a new file if there is no associated block.