package main
import (
"fmt"
"unicode"
"strings"
)
/*
extractDigits
-------------
Walks through the input string and collects only characters
that are classified as digits by the Unicode standard.
Using unicode.IsDigit ensures correct behavior for all
Unicode digit characters, not just ASCII '0'–'9'.
A strings.Builder is used for efficient string construction.
*/
func extractDigits(s string) string {
var b strings.Builder
// Iterate over runes to correctly handle Unicode input
for _, r := range s {
// Check whether the rune is a digit
if unicode.IsDigit(r) {
b.WriteRune(r)
}
}
// Return the collected digits
return b.String()
}
func main() {
// Example input string
str := "5 ruby8go 9001 c c++ go 173python"
// Extract digits
digits := extractDigits(str)
// Display results
fmt.Println("Original:", str)
fmt.Println("Digits: ", digits)
}
/*
run:
Original: 5 ruby8go 9001 c c++ go 173python
Digits: 589001173
*/
