strings

JavaScript - Strings

Strings are one of the data types of JavaScript, where they are used to store sequence of characters.

• ' ' or " " - used to represent values of a string.
• String.length - used to find how many characters are present in the string.
• string[2] - used to get the specific character

Concatenation

• There are two ways to concatenate a two or more strings.

  1. Using + operator.

     let firstName = "Ratan";
     let lastName = "Tata";
     let fullName = firstName + " " + lastName;

  2. Using Template Literals.

     let firstName = "Ratan";
     let lastName = "Tata";
     let fullName = `${firstName} ${lastName}`;

     • There are many things we can do with Template literals.
       • Define strings.

         let avenger = `ironman`

       • Quote inside strings.

         let stringWithQuote = `He's often called "Ironman"`

       • Define multiline strings.

         let multilineString =
         `He's 
         often 
         called 
         "Ironman"`;

       • Define interpolate variables and expressions into strings.

         let firstName = "Ratan";
         let lastName = "Tata";
         let fullName = `${firstName} ${lastName}!`;
         let radius = 10;
         const PI = 3.14;
         let areaOfCircle = `Area of circle: ${PI * (radius**2)}`;

Methods

• toLowerCase() - used to make a string to lower case characters.
• toUpperCase() - used to make a string to upper case characters.
• indexOf('') - used to get the index of particular character.
  • if the character is present, it will return a number.
  • if the character is not present, it will return -1 number as result.
• lastIndexOd('') - same as indexOf() but finds the last occurrence.
• slice() - used to get the sub string from a string by taking start and end index values as input.

let avenger = "Ironman";
let lowerCaseOfAvenger = avenger.toLowerCase();
let upperCaseOfAvenger = avenger.toUpperCase();
let indexOfN = avenger.indexOf("n");
let lastIndexOfN = avenger.lastIndexOf("n");
let slicedAvenger = avenger.slice(2, 5);