Question

我有一个带浮点值的数据集：

dog-auto        dog-bird        dog-cat         dog-dog         Result
41.9579761457   41.7538647304   36.4196077068   33.4773590373   0
46.0021331807   41.33958925     38.8353268874   32.8458495684   0
42.9462290692   38.6157590853   36.9763410854   35.0397073189   0
41.6866060048   37.0892269954   34.575072914    33.9010327697   0
39.2269664935   38.272288694    34.778824791    37.4849250909   0
40.5845117698   39.1462089236   35.1171578292   34.945165344    0
45.1067352961   40.523040106    40.6095830913   39.0957278345   0
41.3221140974   38.1947918393   39.9036867306   37.7696131032   0
41.8244654995   40.1567131661   38.0674700168   35.1089144603   0
45.4976929401   45.5597962603   42.7258732951   43.2422832585   0

这是一个SFrame。我试图编写一个函数，它使用if / an语句来确定dog-dog的值是否小于dog-ct和dog-auto和dog-bird的值。

我经历了4个小时的大部分时间。不可否认，我是python的新手 - 我犯了一个错误，只是没有看到它。

如果声明：

def is_dog_correct(row):
    if (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-cat']]) & (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-bird']]) & (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-auto']]):
        dog_distances['Result'] = 1
    else:
        dog_distances['Result'] = 0

然后我用以下函数调用该函数：

dog_distances.apply(is_dog_correct)

如果这个工作正常，我会在每一行看到“0”，但第五条记录。我的if语句出了什么问题？

完全披露 - 这是课程作业，但在花了4个小时后，我正在寻求帮助！

Answer 1

改变＆amp;并且如前面的评论所示。另外，我建议你把这么长的if语句分成多行，这样就更清晰，更容易阅读。

def is_dog_correct(row):
    if (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-cat']]) and 
       (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-bird']]) and
       (dog_distances[dog_distances['dog-dog']] < dog_distances[dog_distances['dog-auto']]):
        dog_distances['Result'] = 1
    else:
        dog_distances['Result'] = 0

Answer 2

通过查找所有值的min（最小值），使您的第一个if语句更加干净。这确保了“狗狗”＃39;比其他所有人都少：

def is_dog_correct(row):
    if dog_distances[dog_distances['dog-dog']] < min([dog_distances[dog_distances['dog-'+x]] for x in ['cat','bird','auto']]):
        dog_distances['Result'] = 0
    else:
        dog_distances['Result'] = 1

编辑：出于调试目的，请使用以下命令：

def is_dog_correct(row):
    print 'dog is {}'.format(dog_distances[dog_distances['dog-dog']])
    print 'everyone else is {}'.format([dog_distances[dog_distances['dog-'+x]] for x in ['cat','bird','auto']])
    if dog_distances[dog_distances['dog-dog']] < min([dog_distances[dog_distances['dog-'+x]] for x in ['cat','bird','auto']]):
        print 'Yay dog is faster'
        dog_distances['Result'] = 0
    else:
        print 'Awww, dog is not faster'
        dog_distances['Result'] = 1

我的if /和语句中的哑错误 - 没有看到它

2 个答案: