Как отделить целое число от строки

Попробуйте перебрать строку назад, чтобы определить, где начинается последняя числовая или дробная часть:

package main

import (
    "fmt"
    "unicode"
)

// SeparateToken tries to separate a string into two parts:
//   - token1 (the part before the last numeric or fractional part)
//   - token2 (the last numeric or fractional part)
func SeparateToken(token string) (string, string) {
    n := len(token)
    for i := n - 1; i >= 0; i-- {
        if !unicode.IsDigit(rune(token[i])) && token[i] != '/' {
            return token[:i+1], token[i+1:]
        }
    }
    // If no numeric or fractional part is found, return the entire token as token1.
    return token, ""
}

func main() {
    testCases := []string{
        "abc10",
        "hello abc1",
        "final count3/2",
        "xyz",
        "apple 32 banana 10",
    }
    for _, testCase := range testCases {
        token1, token2 := SeparateToken(testCase)
        fmt.Printf("%q -> token1: %q, token2: %q\n", testCase, token1, token2)
    }
}

Выход:

"abc10" -> token1: "abc", token2: "10"
"hello abc1" -> token1: "hello abc", token2: "1"
"final count3/2" -> token1: "final count", token2: "3/2"
"xyz" -> token1: "xyz", token2: ""
"apple 32 banana 10" -> token1: "apple 32 banana ", token2: "10"

Try on Go Playground