Difference Betwixt Substr Vs Substring Method Inwards Javascript - Tutorial Example

JavaScript provides 2 like looking String manipulation function, substr together with substring, though both are used to instruct substring from an String, in that place is a subtle difference betwixt substring together with substr method inwards JavaScript. If you lot aspect at in that place signature, both substr(to, length) together with substring(to, from) both takes 2 parameters, but substr takes length of substring to hold out returned, piece substring takes terminate index (excluding) for substring.This master copy departure volition hold out to a greater extent than clear when nosotros volition run into twosome of examples of using substr together with substring inwards JavaScript code. By the way this is besides a skilful JavaScript enquiry together with oftentimes asked to spider web developers during HTML, CSS together with JavaScript interviews, along amongst how to preclude multiple submission of shape data. Because of extensive uses of String, this cognition is non solely of import from interview betoken of persuasion but besides from evolution betoken of view. It besides helps to trim back subtle bugs inwards JavaScript code, which is innovate because of wrong utilization of substr or substring method.

Difference betwixt SubString together with SubStr method inwards JavaScript

As I said inwards showtime paragraph, master copy departure betwixt substring together with substr JavaScript method are inwards in that place minute parameter, substring direct maintain index of in conclusion grapheme + 1, piece substr() method gets expected length of substring. Let's  convey a aspect at next examples :

var str = "JavaScript";

alert(str.substring(0, 4));  // would impress "Java"

Since JavaScript index are zip based, In inwards a higher house lawsuit starting index is zip (including), which is showtime grapheme together with terminate index is 4 (excluding), together with thence substring would hold out "Java". On the other hand, if nosotros apply like declaration to substr method, nosotros volition instruct same result, but on unlike way.

var str = "JavaScript"

alert(str.substr(0, 4));  // this volition besides render "Java"

Though this code besides returns Java, but hither logic is different, equally hither starting index is zip together with length of substring is 4, which agency 4 characters long string, which starts from showtime character, that's why "Java". If nosotros apply unlike declaration nosotros volition instruct unlike effect e.g.

var str = "JavaScript"

alert(str.substr(4, 6)); // this volition render Script

alert(str.substring(4, 6)); // this volition render "Sc"

Here, you lot tin clearly run into that both substr and substring are returning unlike result, because starting index is non zero. Because of this many spider web developer often confuse together with they think that substr and substring deport identically, which is non true. You should hold out real careful, piece using substr() and substring(), otherwise it volition exercise difficult to discovery subtle bugs. There is approximately other method called slice() which tin besides hold out used for creating smaller substring from String inwards JavaScript, together with you lot tin think of it to avoid whatsoever confusion betwixt substring together with substr in JavaScript.

That's all most difference betwixt substr together with substring method inwards JavaScript, only recollect that departure is inwards the minute argument. The minute declaration of substring method takes terminate index, which is excluded from concluding substring, piece minute declaration of substr method takes maximum length of expected substring.

Further Learning
JavaScript Fundamentals yesteryear Liam McLennan
ES6 Javascript: The Complete Developer's Guide
JavaScript: Understanding the Weird Parts

Sumber https://javarevisited.blogspot.com/

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