TypeError:"NoneType"类型的对象没有len()python

Question

我一直收到这个错误

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

这是代码:

def main():
    myList = [ ]
    myList = read_csv()
    ## myList = showList(myList)
    searchList = searchQueryForm(myList)
    if len(searchList) == 0:
        print("I have nothing to print")
    else:
        showList(searchList)

Answer 1

searchQueryFormNone如果一无所获,显然会返回一个.既然你不能申请len到None,你必须检查,明确:

if searchList is None or len(searchList) == 0: