类型错误; 必须在python 3.x中使用关键字参数或键函数

Question

我是python的新手,尝试将2.x中的脚本移植到3.xi遇到错误TypeError; 必须在python 3.x中使用关键字参数或键函数.下面是一段代码:请帮忙

def resort_working_array( self, chosen_values_arr, num ):
    for item in self.__working_arr[num]:
        data_node = self.__pairs.get_node_info( item )

        new_combs = []
        for i in range(0, self.__n):
            # numbers of new combinations to be created if this item is appended to array
            new_combs.append( set([pairs_storage.key(z) for z in xuniqueCombinations( chosen_values_arr+[item], i+1)]) - self.__pairs.get_combs()[i] )
        # weighting the node
        item.weights =  [ -len(new_combs[-1]) ]    # node that creates most of new pairs is the best
        item.weights += [ len(data_node.out) ] # less used outbound connections most likely to produce more new pairs while search continues
        item.weights += [ len(x) for x in reversed(new_combs[:-1])]
        item.weights += [ -data_node.counter ]  # less used node is better
        item.weights += [ -len(data_node.in_) ] # otherwise we will prefer node with most of free inbound connections; somehow it works out better ;)

    self.__working_arr[num].sort( key = lambda a,b: cmp(a.weights, b.weights) )

Answer 1

看起来问题出在这一行.

self.__working_arr[num].sort( key = lambda a,b: cmp(a.weights, b.weights) )

该key调用应该只取一个参数.尝试:

self.__working_arr[num].sort(key = lambda a: a.weights)

Answer 2

如果尝试将key参数作为位置参数传递，则会出现完全相同的错误消息。

错误：

sort(lst, myKeyFunction)

正确：

sort(lst, key=myKeyFunction)

的Python 3.6.6