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See the related link below for the Java API documentation for the Hashtable class and its methods.

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What is hash key?

hash key is an element in the hash table. it is the data that you will combine (mathematical) with hash function to produce the hash.


Advantage and distadvantage in hash table?

ANSWER A hash table is a way to find data in an array, when you have a known key and an unknown value that corresponds to the key. You use a hashing function on the key to create an index into the hash table containing the value. In the ideal case, this directly returns the corresponding value. In the usual case, a collision can occur. This means that the hashed key points to multiple possible values. A hash table is usually used on large arrays that would take a long time to search using other methods. A hash table can be very fast and use very little memory, and does not require the array to be sorted. The source code is slightly more complicated than some search methods. With a poorly designed hashing function when the hashed keys do not correspond one-to-one with the values, the secondary search after a hash collision can take a large amount of time.


Design a data structure for implement a dictionary by using hash table?

To implement a dictionary using a hash table, you can create a class HashTable that contains an array of linked lists (or buckets) to handle collisions. Each element in the array represents a hash index, where the key-value pairs are stored as nodes in a linked list. The hash function maps keys to indices in the array, allowing for efficient O(1) average time complexity for insertions, deletions, and lookups. Additionally, implement methods for adding, removing, and retrieving values associated with keys, along with a resizing mechanism to maintain performance as the number of entries grows.


How do you use hash table?

In computer science, a hash table, or a hash map, is a data structure that associates keys with values. The primary operation it supports efficiently is a lookup: given a key (e.g. a person's name), find the corresponding value (e.g. that person's telephone number). It works by transforming the key using a hash function into a hash, a number that is used as an index in an array to locate the desired location ("bucket") where the values should be. Hash tables support the efficient insertion of new entries, in expected O(1) time. The time spent in searching depends on the hash function and the load of the hash table; both insertion and search approach O(1) time with well chosen values and hashes.


What difference does it make if you remove a period in a hash?

It makes a big difference because if you compared the hash: abcde.fg = hash 1 to abcdefg = hash 3 The results hash 1 and hash 3 are not equal.

Related Questions

What is hash key?

hash key is an element in the hash table. it is the data that you will combine (mathematical) with hash function to produce the hash.


What is hash table in sql?

temp table


Advantage and distadvantage in hash table?

ANSWER A hash table is a way to find data in an array, when you have a known key and an unknown value that corresponds to the key. You use a hashing function on the key to create an index into the hash table containing the value. In the ideal case, this directly returns the corresponding value. In the usual case, a collision can occur. This means that the hashed key points to multiple possible values. A hash table is usually used on large arrays that would take a long time to search using other methods. A hash table can be very fast and use very little memory, and does not require the array to be sorted. The source code is slightly more complicated than some search methods. With a poorly designed hashing function when the hashed keys do not correspond one-to-one with the values, the secondary search after a hash collision can take a large amount of time.


What is the major advantage of a hash table?

The major advantage of a hash table is its speed. Because the hash function is to take a range of key values and transform them into index values in such a way that the key values are distributed randomly across all the indices of a hash table.


What is the optimal hash table size for achieving efficient performance when dealing with prime numbers?

The optimal hash table size for efficient performance when dealing with prime numbers is typically a prime number that is close to but not exceeding the desired capacity of the hash table. This helps reduce collisions and ensures a more even distribution of values across the table, leading to better performance.


What are the different types of collision resolution techniques?

Open addressing (closed hashing), The methods used include: Overflow block & Closed addressing (open hashing) The methods used include: Linked list, Binary tree..


Insert value into hash table?

Insertion in hash tables is based on a 'key' value which is calculated on the basis of a hash function. This hash function generates the key based on what type of data it is fed. For example hash function for an integer input might look like this : int hash(int val) { return (val%101); } where return value of hash function would become a key. Complete implementation can be found at: http://simplestcodings.blogspot.com/2010/07/hash-table.html


What are the latest advancements in hash computer technology and how are they revolutionizing data encryption methods?

The latest advancements in hash computer technology involve the development of more efficient algorithms and hardware for generating and processing cryptographic hash functions. These advancements are revolutionizing data encryption methods by enhancing security, speed, and scalability in protecting sensitive information from unauthorized access or tampering.


How do you use hash table?

In computer science, a hash table, or a hash map, is a data structure that associates keys with values. The primary operation it supports efficiently is a lookup: given a key (e.g. a person's name), find the corresponding value (e.g. that person's telephone number). It works by transforming the key using a hash function into a hash, a number that is used as an index in an array to locate the desired location ("bucket") where the values should be. Hash tables support the efficient insertion of new entries, in expected O(1) time. The time spent in searching depends on the hash function and the load of the hash table; both insertion and search approach O(1) time with well chosen values and hashes.


What are the different methods for attaching table legs securely to a table?

There are several methods for attaching table legs securely to a table. Some common methods include using metal brackets, screws, dowels, or mortise and tenon joints. Each method has its own advantages and can provide a strong and stable connection between the table legs and the tabletop.


What is hashing and its concepts in data structure?

Hashing allows us to map data of arbitrary length to data of fixed length. If we consider a table that contains thousands of objects, searching for a particular object could have a significant runtime cost if the objects require complex comparisons. Binary search would reduce that cost, however the cost of sorting the objects and then maintaining the order can be just as significant. Instead, we use a hash table. With a suitable hashing function, any object can be reduced to a single value. The range of output values is usually much smaller than the range of input values, thus two or more objects may well produce the same hash value. However, with an appropriate hash function, objects can be evenly distributed throughout the range of hash values. If we suppose that a single hash might be associated with up to n objects, then the size of the hash table will be up to n times smaller than the object table and can therefore be sorted and maintained n times more quickly than the object table. We then only need to sort n objects per hash to create an efficient hash lookup table. To search for an individual object, we pass the object through the hash function to obtain its hash and then search the hash table using a trivial binary search. If the hash exists (with a fixed-length table it is guaranteed to exist), we then use the more complex object comparisons to binary search the n objects associated with that hash value. The end result is that we narrow the search down to a much smaller subset of objects, thus significantly reducing the cost of searching. Hashing has other uses, particularly in cryptography. While it is possible to reverse engineer a hash value to produce n possible values for a given hash, cryptographic hashing is one-way only; we cannot use the hash to reproduce the input. Thus instead of storing passwords, we need only store the hashes produced by those passwords. Even knowing the precise implementation details of the hashing function won't help an attacker because in order to produce a particular hash value you'd still need to know which input actually produces it and that means testing each potential input individually. Doing it for just one input is hard enough, but doing it for two or more is nigh-on impossible (usernames, IP addresses, secret questions and answers and all other security information can also be hashed).


In data mining how do you count True Positive False Negative False Positive and True Negative in a confusion matrix with more than two classes?

There is no automated way of calculating the TP,TN,FP,& FN. You have to determing them manually or atleast the TP. What you can do is create a hash table and enter all the true matches or the true positives. You can then call the hash table in a hash map and detemine the accuracy of your output that's what i did for my paper. Hope this helps