javascript convert string to float

To convert a string to a float in JavaScript, use the parseFloat() function. It parses a string and returns a floating-point number, ignoring leading whitespace and stopping at the first invalid character.

Basic usage: parseFloat("123.45") returns 123.45.
Handles non-numeric prefixes: parseFloat("abc123.45") returns 123.45.
Returns NaN if the first non-whitespace character cannot be converted: parseFloat("abc") returns NaN.
Supports scientific notation: parseFloat("1.23e4") returns 12300.
Trims whitespace: parseFloat(" 45.67 ") returns 45.67.

For strings using commas as decimal separators (e.g., French format), replace commas with dots first:
parseFloat("123,45".replace(",", ".")) returns 123.45.

Alternatively, use the unary plus operator (+) for a concise conversion:
+ "123.45" returns 123.45.

Note: parseFloat() is more lenient than Number() — it ignores trailing invalid characters, while Number() returns NaN if the entire string isn’t a valid number.

How to convert string into float in JavaScript?

stackoverflow.com › questions › 642650 › how-to-convert-string-into-float-in-javascript

If they're meant to be separate values, try this:

var values = "554,20".split(",")
var v1 = parseFloat(values[0])
var v2 = parseFloat(values[1])

If they're meant to be a single value (like in French, where one-half is written 0,5)

var value = parseFloat("554,20".replace(",", "."));

Answer from Jesse Rusak on Stack Overflow

Mozilla

developer.mozilla.org › en-US › docs › Web › JavaScript › Guide › Data_structures

JavaScript data types and data structures - JavaScript | MDN

It is also the only value in JavaScript that is not equal to itself. Although a number is conceptually a "mathematical value" and is always implicitly floating-point-encoded, JavaScript provides bitwise operators. When applying bitwise operators, the number is first converted to a 32-bit integer.

MDN Web Docs

developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › parseFloat

parseFloat() - JavaScript | MDN

The parseFloat() function parses a string argument and returns a floating point number.

Discussions

Converting a string to a float in Javascript?

+"3.4" => 3.4 More on reddit.com

r/javascript

March 27, 2015

Convert string to Float

Hello Everyone! I didn’t find such topic. So I decide to to set up a topic. I couldn’t find at script manual the function to convert string to float. I tried to use the Python function a = "52525238,27337273,83495772" float(a) or int(a) but it didn’t work. Can somebody help me with this? More on forum.universal-robots.com

forum.universal-robots.com

July 14, 2017

What is the fastest way to convert string to float out of these 13 methods?

Well most of those won't cast to a float as they're bitwise operations. But in general, use parseFloat. Don't prematurely optimise. More on reddit.com

r/javascript

February 10, 2018

Library/function that will tidy up weird JS float values without converting to string in between?

If precision is important, then just use integers for everything and convert to floats only at the end for the UI; if you want to round to a specific precision then just multiply your floats into ints, round, and then divide back down again: function round(number, precision = 1){ return Math.round( number * Math.pow(10, precision) ) / Math.pow(10, precision); } // with int rounding round(0.2 + 0.1); // 0.3 // without int rounding // 0.2 + 0.1 = 0.30000000000000004 More on reddit.com

r/learnjavascript

July 13, 2024

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