表示数字

https://www.nowcoder.com/practice/637062df51674de8ba464e792d1a0ac6?tpId=37&tags=&title=&diffculty=0&judgeStatus=0&rp=1

while True:
    try:
        s = input()
        ans = ''
        for i, ch in enumerate(s):
            # left
            if ch.isdigit() and (i - 1 < 0 or s[i-1].isalpha()):
                ans += '*'
            ans += ch
            if i < len(s) and ch.isdigit() and (i + 1 == len(s) or s[i+1].isalpha()):
                ans += '*'
        print(ans)
    except:
        break