无法返回空字符串

Question

＆＃34;我无法根据此问题返回空字符串，问题的第一部分效果很好，但关于＆＃34;空字符串＆＃34;问题我无法返回＆＃34;

Given a string s, return a string made of the first 2
# and the last 2 chars of the original string,
# so 'spring' yields 'spng'. However, if the string length
# is less than 2, return instead the empty string.
     def both_ends(s):
# +++your code here+++
         if s <=2:
               return s[:0]
         else :
               return s[0:2] + s[-2:]

Answer 1

您需要检查输入的len()，然后检查return ''：

def both_ends(s):
    if len(s) < 2:
        return ''
    else:
        return s[:2] + s[-2:]