INTRODUCTION

We all start our programming journey, irrespective of the language we choose, with the message "HELLO WORLD!". A String is nothing but a collection of characters. In this case, it is a collection of words forming "HELLO WORLD!". This means we all are familiar with String but, let us, deep dive, into this easy but most important topic in Java and understand various methods of String. So without any further ado

String : Definition

In Java, the string is basically an object that represents a sequence of char values. An array of characters works the same as a Java string. Strings are used for storing sentences/text. A String variable contains a collection of characters surrounded by double quotes "< text >"

Though String is a class it can be used as a data type which you can see from the above example. It is a non-primitive datatype. Remember that, a String is immutable and cannot be changed, we can sort of update it but the original value remains in the memory once assigned!

A String is instantiated as follows in Java :

DIFFERENT METHODS OF PRINTING

Before understanding various methods understand this :

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We can use the following methods to print in Java Language :

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In the above method, System.out.format() and System.out.printf() are the same so it depends on the Developer as to which to choose. Let's see how to use them with an example :

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String Methods

They are methods in String to find out about various aspects of String. For example about its length, etc. To convert the existing string into lower/upper case. Remember as mentioned earlier the string is immutable and it does not change, the original string remains in the memory. Let me now tell you all the methods in string :

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🟣 Some of the commonly used String methods are 🟣

📌1) name.length() - Tells us the length of the string which is 7 in this case

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📌2) name.toLowerCase() - Returns a new String that has all the characters in lowercase

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📌3) name.toUpperCase() - Returns a new string that has all the characters in uppercase

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📌4) name.trim() - Returns a new String after removing all the leading and trailing spaces from the original string

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📌5) name.substring(int start) - Return a substring from start to end

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📌6) name.substring(int start, int end) - Return a substring from int start way upto the int before the int end. The last index no. is always excluded

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📌7) name.replace("char to be replaced", "char to be added") - Returns a new string after the the replacement

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📌8) name.startswith("Vi") - Returns true if the string starts with "Vi"

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📌9) name.endswith("ak") - Returns true if the string ends with "ak"

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📌10) name.charAt (index number) - Returns the char present in the mentioned index position

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📌11) name.indexOf("char") - Returns index of the given string. Here in the below example, "a" is in the 3rd position also and the 5th position also but it will return the 3rd value because it is first! Returns -1 if match not found

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📌12) name.indexOf("char", index number) - Return the index of the given string starting from the index position mentioned after the comma, and everything before is ignored! Returns -1 if match not found

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