Question

我正在寻找一种更加pythonic方式或更好的做法来简化过滤数据。基本上，我有类结构数据，我想选择和分组属性。有没有一种很好的方法可以做到这一点，而不是扁平化为表格格式？

示例：

class Point:
    def __init__(self, x, y)
        self.x = x
        self.y = y

class Square:
    def __init__(self,origin,length,rotation,color):
        self.origin = origin
        self.length = length
        ...


#populated with all squares
square_list = get_squares()

#create x,y map of all squares
XYindex = defaultdict(list)
for square in square_list:
    XYindex[str(square.origin.x)+','+str(square.origin.y)].append(square)


colorindex = defaultdict(list)
for square in square_list:
    colorindex[str(square.color)].append(square)

#find black squares at 0,0
result = []
for square in colorindex['black']:
    if square in XYindex['0,0']:
        result.append(square)

Answer 1

你可以使用这样的列表理解：

result = [square for square in colorindex['black'] if square in XYindex['0,0']]

list comprehension是在逻辑不复杂时过滤数据的简单方法。

使用Python索引分层数据

1 个答案: