JavaScript / ECMAScript

Float / Scientific Number in JS

Match floating-point and scientific-notation numbers including `1.5`, `.25`, `1e10`, `-3.14E-2`.

Try it in the JS tester →

Pattern

regexJS
[-+]?(?:\d+\.?\d*|\.\d+)(?:[eE][-+]?\d+)?   (flags: g)

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("[-+]?(?:\\d+\\.?\\d*|\\.\\d+)(?:[eE][-+]?\\d+)?", "g");
const input = "h = 6.626e-34, c = 3e8, alpha = .007";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

How the pattern works

[-+]? matches an optional sign. (?:\d+\.?\d*|\.\d+) matches the mantissa as either digits-with-optional-decimal or decimal-with-trailing-digits. (?:[eE][-+]?\d+)? matches the optional exponent. Covers most real-number literals you'll encounter in source or data.

Examples

Input

h = 6.626e-34, c = 3e8, alpha = .007

Matches

  • 6.626e-34
  • 3e8
  • .007

Input

Range -1.5 to +2.5

Matches

  • -1.5
  • +2.5

Input

no numbers here

No match

—

Same pattern, other engines

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

Go (RE2)

Supported

See how this pattern looks (and behaves) in Go's `regexp` package (RE2 engine).

← Back to Float / Scientific Number overview (all engines)