Go (RE2)

Python Package Name (PEP 508) in GO

Validate Python distribution package names per PEP 508: letters, digits, dots, underscores, hyphens.

Try it in the GO tester →

Pattern

regexGO
^[A-Za-z0-9](?:[A-Za-z0-9._\-]*[A-Za-z0-9])?$

Go (RE2) code

goGo
package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`^[A-Za-z0-9](?:[A-Za-z0-9._\-]*[A-Za-z0-9])?$`)
	input := `requests`
	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

Starts and ends with alphanumeric. Allows `_`, `.`, `-` in the middle. The single-char form (just an alphanumeric) is also valid. PEP 508 / PEP 503 normalize all of `_`, `.`, `-` to a single `-` for matching, but the underlying name on PyPI may use any.

Examples

Input

requests

Matches

  • requests

Input

django-rest-framework

Matches

  • django-rest-framework

Input

_invalid

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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