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JavaScript

Posted by Victor Gordian
Victor Gordian
4,656 Points

What does .indexOf mean?

if can please dumb it down so that i can understand it , thank you!

Example

Search a string for "welcome":

var str = "Hello world, welcome to the universe."; var n = str.indexOf("welcome"); The result of n will be:

13

how is it 13? why?

1 Answer

Igor Yamshchykov
Igor Yamshchykov
24,397 Points 
var str = "Hello world, welcome to the universe."; 
var n = str.indexOf("welcome");

this will find the word 'welcome' and return the index of the first letter ( so it's where the first letter of this word appears )

you have string "Hello world, welcome to the universe."u for instance element on index 3 will be letter 'l', because string indexes begin with 0, so when you call 

var n = str.indexOf("welcome");

you will get index of letter 'w', which is 13. Hope that helps.

Victor Gordian
Victor Gordian
4,656 Points

i get that it finds the word where it appears, but how did it get 13? what is being added up?

Igor Yamshchykov
Igor Yamshchykov
24,397 Points

take a look string "Hello world, welcome to the universe." the string begins from index 0, so

H - has index 0,

e - 1,

l - 2,

l - 3,

o - 4,

' ' - 5,

w - 6,

o - 7,

r - 8,

l - 9,

d - 10,

, - 11,

' ' - 12,

w - 13,

e - 14,

and so on.

it finds the word 'welcome' and returns the index of the first letter in this word, as you can see from above it's 13.

Victor Gordian
Victor Gordian
4,656 Points

ohhh it adds everything, i thought just letters. I get it, thank you!