Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles on Trending Technologies
Technical articles with clear explanations and examples
Find the index of the first unique character in a given string using C++
Given a string ‘s’, the task is to find the first unique character which is not repeating in the given string of characters and return its index as output. If there are no such characters present in the given string, we will return ‘-1’ as output. For example, Input-1 −s = “tutorialspoint”Output −1Explanation − In the given string “tutorialspoint”, the first unique character which is not repeating is ‘u’ which is having the index ‘1’. Thus we will return ‘1’ as output.Input-2 −s = “aaasttarrs”Output −-1Explanation − In the given string “aaasttarrs’, there are no unique characters. So, we will ...
Read MoreDetect Capital in a given string using C++
Let's suppose we have a string ‘str’ which consists of some character in it. The task is to check whether the given string has all its characters capitalized or not and return True or False respectively. For example, Input-1 −str = “INDIA”Output −TrueExplanation − Since all the character of the input string is capital, we will return true in this case.Input-2 −str = “Programmer”Output −FalseExplanation − Since all the characters of the input string are not in the capital except the first letter, we will return false in this case.The approach used to solve this problemIn the given string, we ...
Read MoreC++ Program to Delete the First Node in a given Singly Linked List
A linked list is a linear data structure that has multiple nodes that are connected with each other. Each node consists of two fields – Data Field and the address of the next node.Let us assume we have a singly linked list and we need to delete the first node from this linked list. For example, Input 1 − 4 → 3 → 2 → 1Output − 3 → 2 → 1 →Explanation − ‘4’ is the first node in the given singly linked list. After deleting the first node, the linked list will be 3→2→1.Input 2 − 1 → ...
Read MoreWhat is the difference between Java and Java EE
JSE (Java Standard Edition)By using JavaSE you can develop stand-alone application ex: adobe reader, anti-virus, media players, etc. Java SE is also known as core java.lang: Language basics.util: Collection framework, events, data structure and other utility classes such as date.io: File operations, and other input and output operations.math: Multi precision arithmetics.nio: Non-blocking I/O framework for Java.net: Classes an API’s related to networking.security: This package provides classes and interfaces such as key generation, encryption, and decryption which belongs to the security framework.sql: Classes and interfaces for accessing/manipulating the data stored in databases and data sources.awt: Classes and interfaces to create GUI ...
Read MoreHow to remove repeated column names in a data.table object in R?
In data analysis, we sometimes deal with duplicated data or just the representation of the data with same name. One such situation is column names are same for two columns in a data.table object. For this purpose, we can make use of which function with the combination of duplicated function and set the output of that duplicate to NULL to remove the repeated column names.Example1Loading data.table package and creating a data.table object −library(data.table) x1
Read MoreMaximum Erasure Value in C++
Given an array of positive integers, the task is to erase a subarray containing all the unique elements. What you get by erasing the subarray is equal to the sum of its elements.Return the maximum sum of the current subarray by erasing the terms before or after it, we can get the maximum sum by erasing exactly one subarray.An array arr is called to be a subarray of a if it forms a contiguous subsequence of a that is if it is equal to a[l], a[l+1], ..., a[r] for some (l, r). For example, Input-1 −arr[ ] = { 1, 2, ...
Read MoreWhat all constraints can be added to a PostgreSQL table?
There are 6 types of constraints that can be generally used with a PostgreSQL table. They are listed and explained below −NOT NULL CONSTRAINTThis is a very common constraint. If there is a particular column that cannot have null values, you add this constraint at the time of table creation. For example, if we create a marks table, which can’t have NULL values for the name, then the table creation command will look like −CREATE TABLE marks( name VARCHAR NOT NULL, roll_no INTEGER, marks_obtained INTEGER );Now, if we try to insert a row into this table, without ...
Read MoreCreate Primary Key on an existing table in PostgreSQL?
Although quite infrequent, you may come across situations wherein you need to define the primary key on an existing table. This can be achieved using the ALTER TABLE statement.The syntax is −ALTER TABLE table_name ADD PRIMARY KEY (column_name1, column_name2, …., columns_nameN)As can be seen from the above syntax, you can define PRIMARY KEY on multiple columns. When you have defined the PRIMARY KEY on multiple columns, the condition is that the column pairs should have unique and non-null values. Thus, if the PRIMARY KEY is defined on (column1, column2), the values (value1, value2), (value3, value2), and (value1, value4) are allowed. ...
Read MoreExtract day, hour, minute, etc. from a datetime column in PostgreSQL?
Let us create a new table containing a single timestamp column −CREATE TABLE timestamp_test( ts timestamp );Now let us populate it with some data −INSERT INTO timestamp_test(ts) VALUES(current_timestamp), (current_timestamp+interval '5 days'), (current_timestamp-interval '18 hours'), (current_timestamp+interval '1 year'), (current_timestamp+interval '3 minutes'), (current_timestamp-interval '6 years');If you query the table (SELECT * from timestamp_test), you will see the following output −ts2021-01-30 19:23:24.0080872021-02-04 19:23:24.0080872021-01-30 01:23:24.0080872022-01-30 19:23:24.0080872021-01-30 19:26:24.0080872015-01-30 19:23:24.008087Now, in order to extract hour, minute, etc. from the timestamp column, we use the EXTRACT function. Some examples are shown below −SELECT EXTRACT(HOUR from ts) as hour from timestamp_testOutput −hour19191191919Similarly −SELECT EXTRACT(MONTH from ts) as ...
Read MoreHow to combine different columns of a table to yield a single column in query output in PostgreSQL?
Suppose you have a table user_info that contains the state and district of different users. An example is given below −namedistrictstateAnilMumbaiMaharashtraJoyJhalawarRajasthanRonPuneMaharashtraReenaMeerutUttar PradeshNow, if you want to combine the state and district in a single field called location, this is how you should be able to do it −SELECT name, district || ', ' || state as location from user_infoThe || operator is the string concatenation operator. The output will be −namelocationAnilMumbai, MaharashtraJoyJhalawar, RajasthanRonPune, MaharashtraReenaMeerut, Uttar PradeshSimilar operations can also be performed on numerical values. Suppose you have a table marks containing the total marks scored by students and the maximum ...
Read More