354 Understanding Hash Tables A B C . Figure 3-7: Hash tables make searching faster by dividing data into distinct sections. V W X Y Hash Table Value Mail Versatile Plumbing Data When you store data with a unique key (a key-value pair), the key is used to help identify and retrieve the data. However, just using a key alone is no better than storing data alone because keys are just another chunk of data. The more data (and keys) you store, the longer it takes the computer to search through its entire list of keys. Converting keys with a hash function To speed up searching, dictionaries use hash tables. Basically, a hash table takes the keys used to identify data and then converts that key into a hash value. This hash value gets stored into a sorted list (table), as shown in Figure 3-8. The exact method used to convert a key into a value is a hash function. The converted key, or hash, now points directly to the stored data. At this point, the computer actually stores just two chunks of data: ✦ The data itself ✦ A hash value calculated from the key When you want to retrieve data, you give the computer the key associated with the data that you want. The computer takes the key and uses its hash function to convert the key to a value.
Understanding Hash Tables 355 VP Key: VP Versatile Plumbing 1. The user assigns a descriptive key with data. 2. The key gets sent to a hash function. Hash Function 3. The hash function converts the key into a value that gets sorted in a hash table. 101 105 102 Figure 3-8: Hash tables convert keys into a numeric value. 103 104 105 106 107 108 Versatile Plumbing 4. The hash value points to the stored data. Now the computer tries to match this calculated value to its list of values stored in the hash table. When it finds a match, it can then find the data associated with that key. A simple hash function might just add up all the characters in a key and use that total as a value. For example, consider the keys moron and imbecile. blackbook := Dictionary new. blackbook at: ‘moron’ put: ‘Dick Ross’. blackbook at: ‘imbecile’ put: ‘John Adams’. Such a simple hash function could create a table like this: Book III Chapter 3 Collections and Dictionaries Hash table Data 5 Dick Ross 8 John Adams
Agreed in 2016, the motive of the General Data Protection Regulation (GDPR) is to better protect the personal data of European Union “data subjects” – EU citizens and other nationals physically present in the EU at the time data are collected. Visit: https://www.hipaajournal.com/gdpr-training/
The Health Insurance Portability and Accountability Act (HIPAA) was created primarily to modernize the flow of healthcare information, stipulate how Personally Identifiable Information maintained by the healthcare and healthcare insurance industries should be protected from fraud and theft, and address limitations on healthcare insurance coverage – such as portability and the coverage of individuals with pre-existing conditions.