返回 int 的错误在 python 3.8.3 中没有 len

Question

我面临一个int has no len的问题。

下面是代码和问题

def find_pair(inArr):
    outStr = -1
    for i in range(len(inArr)):
        for j in range(i+1, len(inArr)):
            if len(set(inArr[i]) | set(inArr[j])) == 6:
                if len(inArr[i] + inArr[j]) > len(outStr):
                    outStr = inArr[i] + inArr[j]
    return outStr

inArr = ["30012","250232","53201","3004355","124111"]
print(find_pair(inArr))

output 如下

TypeError                                 Traceback (most recent call last)
<ipython-input-7-6a7c01fe00b4> in <module>
      9 
     10 inArr = ["30012","250232","53201","3004355","124111"]
---> 11 print(find_pair(inArr))

<ipython-input-7-6a7c01fe00b4> in find_pair(inArr)
      4         for j in range(i+1, len(inArr)):
      5             if len(set(inArr[i]) | set(inArr[j])) == 6:
----> 6                 if len(inArr[i] + inArr[j]) > len(outStr):
      7                     outStr = inArr[i] + inArr[j]
      8     return outStr

TypeError: object of type 'int' has no len()

预期的 output 是

Input: ["30012","250232","53201","3004355","124111"]
Output: 300123004355

和

Input: ["01221","21313","12321"]
Output: -1

谁能帮我解决这个问题？

Answer 1

您将 outStr 定义为 -1，其类型为 integer。 我假设您想将其定义为空字符串。 因此，您必须在比较时减去 1 - 因为空字符串的长度为 0。

修改后的 function 返回所需的值：

def find_pair(inArr):
    outStr = ""
    for i in range(len(inArr)):
        for j in range(i + 1, len(inArr)):
            if len(set(inArr[i]) | set(inArr[j])) == 6:
                if len(inArr[i] + inArr[j]) - 1 > len(outStr):
                    outStr = inArr[i] + inArr[j]
    return outStr or -1

print(find_pair(["30012", "250232", "53201", "3004355", "124111"]))  # 300123004355
print(find_pair(["01221", "21313", "12321"]))  # -1

Answer 2

在这一行中if len(inArr[i] + inArr[j]) > len(outStr):当outStr = -1为 integer 时，您尝试执行此len(outStr)
所以当然你不能测量 integer 的长度，你会得到一个错误