String functions in java

I wrote the following function to convert a time in milliseconds to a string of the format mins:seconds. Being a former C programmer I assumed that "ans" would have to be static in order to work properly, but putting static before String appears to not be allowed. My question is - will this function work - and if not, what change will make it work. public String time_to_string(long t) // time in milliseconds Your code is fine. There's no problem with returning Strings in this manner. In Java, a String is a reference to an immutable object. This, coupled with garbage collection, takes care of much of the potential complexity: you can simply pass a String around without worrying that it would disapper on you, or that someone somewhere would modify it. If you don't mind me making a couple of stylistic suggestions, I'd modify the code like so: public String time_to_string(long t) // time in milliseconds As you can see, I've pushed the variable declarations as far down as I could (this is the preferred style in C++ and Java). I've also eliminated ans and have replaced the mix of string concatenation and String.format() with a single call to String.format(). In Java, a String is a reference to heap-allocated storage. Returning "ans" only returns the reference so there is no need for stack-allocated storage. In fact, there is no way in Java to allocate objects in stack storage. I would change to this, though. You don't need "ans" at all. return String.format("%d:%d", mins, secs);

Example String txt = "Hello World"; System.out.println(txt.toUpperCase()); // Outputs "HELLO WORLD" System.out.println(txt.toLowerCase()); // Outputs "hello world" Finding a Character in a String The indexOf() method returns the index (the position) of the first occurrence of a specified text in a string (including whitespace):

Returns a composed function that first applies the before function to its input, and then applies this function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. Type Parameters: V - the type of input to the before function, and to the composed function Parameters: before - the function to apply before this function is applied Returns: a composed function that first applies the before function and then applies this function Throws: See Also: andThen(Function) • andThen default Returns a composed function that first applies this function to its input, and then applies the after function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. Type Parameters: V - the type of output of the after function, and of the composed function Parameters: after - the function to apply after this function is applied Returns: a composed function that first applies this function and then applies the after function Throws: See Also: compose(Function) • identity static

Output The extracted substring is : geeksforgeeks 2. String substring(begIndex, endIndex) This method has two variants and returns a new string that is a substring of this string. The substring begins with the character at the specified index and extends to the end of this string or up to endIndex – 1 if the second argument is given. Output The extracted substring is : geeks The complexity of the above method Time Complexity: O(n), where n is the length of the original string. The substring() method takes constant time O(1) to return the substring. Space Complexity: O(1), as no extra space is required to perform the substring operation. Possible Application The substring extraction finds its use in many applications including prefix and suffix extraction. For example to extract a Lastname from the name or extract only the denomination from a string containing both the amount and currency symbol. The latter one is explained below. Below is the implementation of the above application

Introduction to String Functions in Java A number of methods provided in Java to perform operations in Strings are called String functions. The methods are compare(), concat(), equals(), split(), length(), replace(), compareTo() and so on. Strings in Java are constant, and it is created either using a literal or using a keyword. String literal is used to make Java memory efficient, and the keyword creates Java string in normal memory. The string represents an array of character values, and the class is implemented by three interfaces such as Serializable, Comparable, and CharSequence interfaces. It represents the sequence of characters in a serialized or comparable manner. Main Concept of string functions in Java Below are the main concepts of String Functions in java: 1. Creating String There are two ways in which a String object can be created in Java: Using a string literal: String literal in Java can be created using double-quotes. Example: String s= "Hello World!"; Using the new keyword: Java String can be created by using the keyword “new”. Example: String s=new String ("Hello World!"); 2. String length Methods that are used to get information about an object are called accessor methods in Java. One such accessor method related to strings is the length () method. This returns the number of characters in the string object. public class Exercise Output: Conclusion Apart from the above-mentioned characteristics, functions, and methods, there are other facts too with th...

In the given example only one object will be created. Firstly JVM will not find any string object with the value “Welcome” in the string constant pool, so it will create a new object. After that it will find the string with the value “Welcome” in the pool, it will not create a new object but will return the reference to the same instance. In this article, we will learn about Java Strings. What are Strings in Java? Strings are the type of objects that can store the character of values. A string acts the same as an array of characters in Java. = ""; 1. String literal To make Java more memory efficient (because no new objects are created if it exists already in the string constant pool). Example: String s = “GeeksforGeeks”; 2. Using new keyword • String s = new String(“Welcome”); • In such a case, JVM will create a new string object in normal (non-pool) heap memory and the literal “Welcome” will be placed in the string constant pool. The variable s will refer to the object in the heap (non-pool) Example: String s = new String (“GeeksforGeeks”); Interfaces and Classes in Strings in Java CharSequence Interface CharSequence Interface is used for representing the sequence of Characters in Java. Classes that are implemented using the CharSequence interface are mentioned below: • String • StringBuffer • StringBuilder 1. StringBuffer String that provides much of the functionality of strings. The string represents fixed-length, immutable character sequences while StringBuffe...

I'd suggest forgetting about Java for this task and use Clojure. Clojure allows you to parse and/or compile code at runtime (and at compile time) and run it, and also to generate code at compile time as well as many other things which are, by the way, pretty usual in the LISP world. Java is too boring. And Clojure can do everything that Java can, because it runs on JVM (although other implementations do exist, too) And it can be mixed with Java seamlessly, even inside one shared project. There is no standard Java class or method that will do what you want. Your options include: • Select and use some third-party expression evaluation library. For example • Wrap the expression in the Java source code for a class with an eval method, send that to the Java compiler, and then load the resulting compiled class. • Use some scripting language that can be called from Java as an expression evaluator. Possibilities include Javascript 1, BeanShell, and so on. A JSR 223 compliant scripting language implementation can be called via the • Write your own expression evaluator from scratch. The first approach is probably simplest. The second and third approaches are a potential security risk if you get the expression to be evaluated from an untrusted user. (Think code injection.) 1 - Javascript in Java SE is a moving target. From Java 6, a version of Mozilla's Rhino Javascript implementation was bundled with Java SE. The in Java 8, it was superseded by Nashorn. In Java 11, Nashorn was depre...

A method is a block of code which only runs when it is called. You can pass data, known as parameters, into a method. Methods are used to perform certain actions, and they are also known as functions. Why use methods? To reuse code: define the code once, and use it many times. Create a Method A method must be declared within a class. It is defined with the name of the method, followed by parentheses (). Java provides some pre-defined methods, such as System.out.println(), but you can also create your own methods to perform certain actions: Example Create a method inside Main: public class Main Example Explained • myMethod() is the name of the method • static means that the method belongs to the Main class and not an object of the Main class. You will learn more about objects and how to access methods through objects later in this tutorial. • void means that this method does not have a return value. You will learn more about return values later in this chapter Call a Method To call a method in Java, write the method's name followed by two parentheses () and a semicolon ; In the following example, myMethod() is used to print a text (the action), when it is called:

A method is a block of code which only runs when it is called. You can pass data, known as parameters, into a method. Methods are used to perform certain actions, and they are also known as functions. Why use methods? To reuse code: define the code once, and use it many times. Create a Method A method must be declared within a class. It is defined with the name of the method, followed by parentheses (). Java provides some pre-defined methods, such as System.out.println(), but you can also create your own methods to perform certain actions: Example Create a method inside Main: public class Main Example Explained • myMethod() is the name of the method • static means that the method belongs to the Main class and not an object of the Main class. You will learn more about objects and how to access methods through objects later in this tutorial. • void means that this method does not have a return value. You will learn more about return values later in this chapter Call a Method To call a method in Java, write the method's name followed by two parentheses () and a semicolon ; In the following example, myMethod() is used to print a text (the action), when it is called:

In the given example only one object will be created. Firstly JVM will not find any string object with the value “Welcome” in the string constant pool, so it will create a new object. After that it will find the string with the value “Welcome” in the pool, it will not create a new object but will return the reference to the same instance. In this article, we will learn about Java Strings. What are Strings in Java? Strings are the type of objects that can store the character of values. A string acts the same as an array of characters in Java. = ""; 1. String literal To make Java more memory efficient (because no new objects are created if it exists already in the string constant pool). Example: String s = “GeeksforGeeks”; 2. Using new keyword • String s = new String(“Welcome”); • In such a case, JVM will create a new string object in normal (non-pool) heap memory and the literal “Welcome” will be placed in the string constant pool. The variable s will refer to the object in the heap (non-pool) Example: String s = new String (“GeeksforGeeks”); Interfaces and Classes in Strings in Java CharSequence Interface CharSequence Interface is used for representing the sequence of Characters in Java. Classes that are implemented using the CharSequence interface are mentioned below: • String • StringBuffer • StringBuilder 1. StringBuffer String that provides much of the functionality of strings. The string represents fixed-length, immutable character sequences while StringBuffe...