Go (RE2)

Float / Scientific Number in GO

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

Try it in the GO tester →

Pattern

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

Go (RE2) code

goGo
package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`[-+]?(?:\d+\.?\d*|\.\d+)(?:[eE][-+]?\d+)?`)
	input := `h = 6.626e-34, c = 3e8, alpha = .007`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}

Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.

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

JavaScript / ECMAScript

Supported

See how this pattern looks (and behaves) in JavaScript's built-in RegExp.

Python (re)

Supported

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

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