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In this article, we are going to discuss how to use regular expressions in place of a string.replace() method. As you may know, Python's built-in string.replace() method is used to replace given substrings in a string. But when we need more complex replacement features so Python's re (regular expressions) module is very helpful. Regular expressions allow us to search for patterns and replace them with precise values, which makes string manipulation simpler. Why Use Regular Expressions? While string.replace() works well for simple tasks, it has its limitations, like it can only replace exact substrings and has limited ability to use pattern ... Read More
In this article we will be using Regular Expression to get zero or more occurrences within the pattern. Regular expressions (regex) are important features to identify patterns in text. In Python, the re module provides support for working with regex. The concept of zero or more occurrences is a key regex feature. This means that a pattern can appear somewhere between zero and an infinite number of times. Zero or More Occurrences? In regex, the * symbol denotes zero or more instances of the preceding element. For example, the pattern a* will match - ... Read More
Type inference (or, type deduction) refers to the automatic detection of the data type of an expression in a programming language. In C++, the auto keyword is used for automatic type deduction.For example, you want to create an iterator to iterate over a vector, you can simply use auto for that purpose.It is helpful, when dealing with complicated STL containers, iterators, and lambda functions where it may be hard to write the full type. This can be achieved using auto, decltype, and decltype(auto) keywords. These approaches help in letting the compiler understand the correct data types without explicitly declaring them. ... Read More
In Python, recursion is a programming technique where a function calls itself to solve a problem. Backtracking means trying different options one by one and going back if one option doesn’t work. It helps in solving problems step by step, like puzzles or finding the right path. How Recursion and Backtracking Work Together Imagine navigating a maze. We are trying a path, and if it hits a dead-end, we go back and try another. That’s backtracking. The steps of trying and going back are done using recursive function calls. Backtracking frequently uses recursion to explore different possibilities ... Read More
The Copy and Swap Idiom in C++ is a technique used in assignment operations. This consists of two steps: Discarding an object's old state and building a new state for it. The destructor is used for the first step and a copy constructor does the second step. Implementing both of these is straightforward. But when overloading the assignment operator, it can become quite difficult to implement. The copy and swap idiom is a solution for the same. This idiom uses the copy-constructor to build a local copy of the data. It then swaps the old data with the new data ... Read More
Concatenate a string and an integer means, convert both the string and integer to a single string. In this article we will discuss all the approches to concatenate a std:string and an integer type using C/C++ program. First of all, let's understand the problem statement. We are given a standard c++ string and an integer. We have to output a single string by combining the given string and integer. For example: // Input String and Integer "Value = " 25 // Output String "Value = 25" Concatenate String and Int in C++ Here is the list ... Read More
Sting Concatenatination is the process of creating a single string from multiple strings by combining them all together. In this article, we will discuss all approaches to concatenate multiple strings using C/C++ program. First of all, let's understand the problem statement. A set of C++ strings are given as input. We need to output a single string which is concatenate of the strings provided. For example: // Input Strings "Value " "is " "Big" // Output String "Value is Big" Concatenate Multiple Strings to Single Line Here is the list of approaches ... Read More
Trigraphs in C++ are special three-character sequences that represent a certain single character, which may not be available on some keyboards or systems. Previously, the ISO-646 character set did not have all the characters of the C syntax; therefore, some systems with their keyboard and display faced problems while dealing with those few characters.So the trigraphs have been introduced, which start with two question marks (??) and are further followed by a third character, which the compiler considers as a particular equivalent single-character. Trigraphs Table in C++ There are a total of nine trigraphs available in C++; here is the ... Read More
In this article, we will be learning how to merge two JSON arrays in Java. Let's understand step by step. First, if you are not familiar with JSON, refer JSON overview. How to Merge Two JSON Arrays in Java? There are multiple ways to merge two JSON arrays in Java. Some of them are: Using org.json library: We will use JSONArray.put() method to merge two JSON arrays. Using Gson library: We will use JsonArray.add() method to merge two JSON arrays. Using Jackson library: We will use ObjectMapper.createArrayNode() ... Read More
JSON is the data interchange format that stores values in key-value pairs. (To learn more about JSON, you can refer to the JSON tutorial). So, as we have key and value in JSON, we will try to get all those keys using the Gson library. Gson Library: Retrieving all the keys of a JSON Gson is a third-party Java library developed by Google. It is used for converting Java objects to JSON and vice versa. To know more about Gson, refer to the Gson tutorial. We can use the keySet() method of JsonObject class to get all the keys of a ... Read More