"无法连接'str'和'int'对象"错误

Question

当我尝试运行以下代码时,我不断收到"无法连接'str'和'int'对象"错误.我指出第6行是问题的根源,但我真的看不出错误!我的类型似乎都是一致的.

def DashInsert(num): 
  num_str = str(num)
  new_str = ''

  for i in num_str:
    var1 = num_str[i:i+1]
    var2 = num_str[i+1:i+2]

    if var1 % 2 == 1 and var2 % 2 == 1:
      new_str = new_str + num_str[i:i+1] + "-"
    else:
      new_str = new_str + num_str[i:i+1]

  return new_str

# keep this function call here  
# to see how to enter arguments in Python scroll down
print DashInsert(raw_input())  

Answer 1

for i in num_str:

i 在这种情况下,它不是索引,它是一个字符串字符.

例如,如果num您的代码是42,那么工作流程将是:

num_str = str(42) # '42'
for i in num_str: # First iteration
    var1 = num_str['4':'4'+1] # Python: '4' + 1 = ERROR

您可能正在寻找的是:

for i, c in enumerate(num_str):
    var1 = num_str[0:0+1] # Python: 0 + 1 = 1

看到这个答案.