03-1-search-and-compare.md

3.1 Search and Compare

3.1.1 Accessing characters

We can use 'chatAt()' to find characters in a String

let str = "Awesome String"
console.log(str.charAt(2)) // e

Since ECMAScript 2015, we can also tread a string like a character array and access characters using the obj[N] syntax like normal arrays.

let str = "Awesome String"
console.log(str[2]) // e

3.1.2 Searching characters

We can search for characters and other strings inside a string using indexOf() method While this only returns the first instance of the occurence, we can search for next occurence by passing a search from index in the second parameter of indexOf(). See example -

let str = "Potato potato"
str.indexOf("o") //1
str.indexOf("to") //4
str.indexOf("to", 5) //11
str.indexOf("o", str.indexOf("o") + 1) //5

As seen above we can recurse on the result of indexOf() to get second instance too.

Javascript allows searching from the other end too, simply using lastIndexOf()

let str = "Potato potato"
str.lastIndexOf("o") //12
str.lastIndexOf("to", 10) //4