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How to Create a Sparse File

Sparse files are files with “holes”. File holes do not take up any physical space as the file system does not allocate any disk blocks for a hole until data is written into it. Reading a hole returns a null byte.

Virtual machine images are examples of spare files. For instance, when I create a VirtualBox machine and assign it a maximum storage of 100Gb, only the storage corresponding to the actual data in the machine is consumed.

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Folding Things With Functional Programming

Folding things can be fun!

Introduction

In this post, we will discuss the concept of fold in functional programming: fold functions are used to reduce a data structure containing multiple values into a single one. Associated to the idea of fold are the concepts of...

  • recursion: via recursion, fold traverses the different elements of the data structure.
  • summarisation: the data structure with all its elements is reduced to a single value
You may also like: 10 Amazing Scala Collection Functions

In the following example, the class Rectangle can be reduced to a single value representing its area. However, it is not 'foldable' in the sense that there is no recursion involved.

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Focus on Your Data Structures With Scala Lenses

With new programming techniques come new problems and new patterns to solve them.

In functional programming, immutability is a must. As a consequence, whenever it is needed to modify the content of a data structure, a new instance with updated values is created. Depending on how complex the data structure is, creating a copy may be a verbose task.