package main
import (
"fmt"
"strings"
"unicode"
)
// RemoveLetters removes all alphabetical letters from the input string,
// leaving behind digits, spaces, and symbols.
func RemoveLetters(input string) string {
var sb strings.Builder
// Pre-allocate memory in the builder buffer up to the length of the input
// to prevent dynamic reallocations during iteration.
sb.Grow(len(input))
// Iterate over the string character by character (handling UTF-8 runes properly)
for _, r := range input {
// Keep the character only if it is NOT an alphabetical letter
if !unicode.IsLetter(r) {
sb.WriteRune(r)
}
}
return sb.String()
}
func main() {
// Test string provided
text := "abc123XYZ456programming789"
// Process the string
cleanedText := RemoveLetters(text)
// Output results
fmt.Printf("Original: %s\n", text)
fmt.Printf("Cleaned: %s\n", cleanedText)
}
/*
run:
Original: abc123XYZ456programming789
Cleaned: 123456789
*/
