对字典列表执行操作

Question

我想通过使用一些自定义质心计算函数向loc1和loc2字典添加一个名为"centroid"的额外键。location_list是字典loc1和loc2的列表

location_list = [loc1,loc2]
loc1 = {
"x_cor" : 10,
"y_cor" : 20}
loc2 = {
"x_cor" : 10,
"y_cor" : 25}

我想获得这两个位置的质心，并添加一个额外的键质心;到loc1和loc2。

质心计算函数如下:

def get_centroid(self, locations: list):

x, y = [p[0] for p in locations], [p[1] for p in locations]
centroid = [round(sum(x) / len(locations), 2), round(sum(y) / len(locations), 2)]
return centroid

预期输出:

loc1 = {
"x_cor" : 10,
"y_cor" : 20,
"centroid": (6.667 , 15)}

loc2 = {
"x_cor" : 10,
"y_cor" : 25,
"centroid": (6.667 , 15)} 

是否有一种方法，我可以使用这个函数来添加一个额外的键"质心"这些字典?

Answer 1

def get_centroid(self, locations: list):

x, y = [p[0] for p in locations], [p[1] for p in locations]
centroid = [round(sum(x) / len(locations), 2), round(sum(y) / len(locations), 2)]
for location in locations:
location['centroid'] = centroid
return centroid

Answer 2

您的get_centroid函数不起作用。由于字典是无序的，因此不能使用索引访问字典项，请将索引放入字典。

这意味着你必须将p[0]替换为p['x_cor']，将p[1]替换为p['y_cor']。

我不认为你需要self作为get_centroid的参数。self不在函数代码中使用，它们主要在类中使用。

要为loc1和loc2添加质心，可以使用for循环。

for loc in locations:
loc['centroid'] = centroid
return locations

将此组合到您的get_centroid函数中得到:

def get_centroid(locations: list):
x, y = [p['x_cor'] for p in locations], [p['y_cor'] for p in locations]
centroid = [round(sum(x) / len(locations), 2), round(sum(y) / len(locations), 2)]
for loc in locations:
loc['centroid'] = centroid
return locations

使用你提供的x和y坐标值和质心方程，我无法达到你预期的输出。我为质心实现的输出是(10.0,22.5)。

整个代码

def get_centroid(locations: list):
x, y = [p['x_cor'] for p in locations], [p['y_cor'] for p in locations]
centroid = [round(sum(x) / len(locations), 2), round(sum(y) / len(locations), 2)]
for loc in locations:
loc['centroid'] = centroid
return locations
loc1 = {
"x_cor" : 10,
"y_cor" : 20}
loc2 = {
"x_cor" : 10,
"y_cor" : 25}
location_list = [loc1,loc2]
print(get_centroid(location_list))

[{'x_cor': 10, 'y_cor': 20, 'centroid': [10.0, 22.5]}, {'x_cor': 10, 'y_cor': 25, 'centroid': [10.0, 22.5]}]