只能将列表（而不是“ int”）连接到列表

Question

我将代码放入IDLE并收到错误消息

  

TypeError：只能将列表（而不是“ int”）连接到列表。

为什么python不接受this.formBuilder.group({ 'eventDates': this.formBuilder.group( { 'startDate': ['someValue'] }, { validator: syncValidator, // validator for eventDates group asyncValidator: asyncValidator // async validator for eventDates group } ) }) 中的索引作为values[index]？ 我该怎么办？

int

Answer 1

尝试一下：

def repeat_elem (values, index, num_times):
    # this function returns a new list in which the element of 'values'
    # at position 'index' has been repeated 'num_times' times
    return values[:index] + ([values[index]] * num_times) + values[index+1:]

在上面的代码中：

• repeat_elem([1, 2, 3], 0, 5)返回[1, 1, 1, 1, 1, 2, 3]
• repeat_elem([1, 2, 3], 1, 5)返回[1, 2, 2, 2, 2, 2, 3]
• repeat_elem([1, 2, 3], 2, 5)返回[1, 2, 3, 3, 3, 3, 3]