How js acquires position by character or character by position

This article mainly shows you "js how to obtain the position through the character or through the position of the character", the content is easy to understand, well-organized, hope to help you solve your doubts, the following let the editor lead you to study and learn "js how to obtain the position through the character or through the position of the character" this article.

Get a position by a character or a character by a position:

/ / return characters console.log (str.charAt (1)); console.log (str [1]); / / return character encoding console.log (str.charCodeAt (1)) at specified position; / / return string position console.log (str.indexOf ("o")); / / No return-1console.log (str.lastIndexOf ("o"))

The result of execution in the browser is as follows:

Suppose there is a variable now:

Var a = 'the furthest distance in the world is not the ends of the earth'

Var b = 'furthest distance'

Now you want to dynamically get the string before the variable b and the string after the variable, you can do this

1. Use slice to get the previous string

two。 Get the length of the variable b, add the length of b after the initial position of b, and truncate the length of a from the tail of b (of course, the length of a can be omitted! )

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