Saya tidak dapat menemukan cara langsung yang bagus, karena dari contoh Anda, Anda tidak ingin memasukkan poin itu sendiri. Saya akhirnya membuat kelompok dan menghitung jarak di dalamnya.
Sunting: Menambahkan variasi yang (harus) menyertakan ID titik terdekat.
from sklearn.neighbors import BallTree
import pandas as pd
import numpy as np
from scipy.spatial.distance import pdist, squareform
df = pd.DataFrame({
'Time' : [1,1,1,1,1,1,2,2,2,2,2,2],
'ID' : ['A','B','C','X','U','V','A','B','C','X','U','V'],
'Group' : ['Red','Red','Red','Grn','Grn','Grn','Red','Red','Red','Grn','Grn','Grn'],
'X' : [2.0,3.0,4.0,2.0,2.0,1.0,1.0,6.0,4.0,2.0,5.0,3.0],
'Y' : [3.0,1.0,0.0,0.0,2.0,1.0,2.0,0.0,1.0,1.0,0.0,0.0],
})
def subgroup_distance(df, group_column='Group', include_point_itself=True):
groups = df[group_column].unique()
all_points = df[['X','Y']].values
for group in groups:
group_points = df[df[group_column] == group][['X','Y']]
tree = BallTree(group_points, leaf_size=15, metric='minkowski')
if include_point_itself:
distance, index = tree.query(all_points, k=1)
distances = distance[:,0]
distance_column_name = "distance_{}".format( group )
df[ distance_column_name ] = distances
else:
indici = (df[group_column] == group).values * 1
distance, index = tree.query(all_points, k=2)
distances = distance[ np.arange(distance.shape[0]), indici]
distance_column_name = "distance_{}".format( group )
df[ distance_column_name ] = distances
return df
def calculate_distances(df):
return subgroup_distance(df, include_point_itself=False)
df_distances = df.groupby(['Time']).apply(calculate_distances).reset_index()
ini akan menghasilkan
index Time ID Group X Y distance_Red distance_Grn
0 0 1 A Red 2.0 3.0 2.236068 1.000000
1 1 1 B Red 3.0 1.0 1.414214 1.414214
2 2 1 C Red 4.0 0.0 1.414214 2.000000
3 3 1 X Grn 2.0 0.0 1.414214 1.414214
4 4 1 U Grn 2.0 2.0 1.000000 1.414214
5 5 1 V Grn 1.0 1.0 2.000000 1.414214
6 6 2 A Red 1.0 2.0 3.162278 1.414214
7 7 2 B Red 6.0 0.0 2.236068 1.000000
8 8 2 C Red 4.0 1.0 2.236068 1.414214
9 9 2 X Grn 2.0 1.0 1.414214 1.414214
10 10 2 U Grn 5.0 0.0 1.000000 2.000000
11 11 2 V Grn 3.0 0.0 1.414214 1.414214
Variasi yang akan menampilkan ID dari titik terdekat dalam subgrup
def subgroup_distance_with_nearest(df, group_column='Group', include_point_itself=True):
groups = df[group_column].unique()
all_points = df[['X','Y']].values
for group in groups:
group_points = df[df[group_column] == group][['X','Y']]
tree = BallTree(group_points, leaf_size=15, metric='minkowski')
distances = None
nearest_id = None
if include_point_itself:
distance, index = tree.query(all_points, k=1)
distances = distance[:,0]
nearest_id = group_points.index[index[:,0]]
else:
indici = (df[group_column] == group).values * 1
distance, index = tree.query(all_points, k=2)
distances = distance[ np.arange(distance.shape[0]), indici]
index_indici = index[ np.arange(distance.shape[0]), indici]
nearest_id = group_points.index[index_indici]
distance_column_nearest_name = "nearest_index_{}".format( group )
distance_column_name = "distance_{}".format( group )
df[ distance_column_name ] = distances
df[ distance_column_nearest_name] = nearest_id
return df
def subgroup_distance_with_nearest(df):
return subgroup_distance(df, include_point_itself=False)
df_distances = df.groupby(['Time']).apply(calculate_distances).reset_index()
dan itu akan menghasilkan
index Time ID Group X Y distance_Red nearest_index_Red \
0 0 1 A Red 2.0 3.0 2.236068 1
1 1 1 B Red 3.0 1.0 1.414214 2
2 2 1 C Red 4.0 0.0 1.414214 1
3 3 1 X Grn 2.0 0.0 1.414214 1
4 4 1 U Grn 2.0 2.0 1.000000 0
5 5 1 V Grn 1.0 1.0 2.000000 1
6 6 2 A Red 1.0 2.0 3.162278 8
7 7 2 B Red 6.0 0.0 2.236068 8
8 8 2 C Red 4.0 1.0 2.236068 7
9 9 2 X Grn 2.0 1.0 1.414214 6
10 10 2 U Grn 5.0 0.0 1.000000 7
11 11 2 V Grn 3.0 0.0 1.414214 8
distance_Grn nearest_index_Grn
0 1.000000 4
1 1.414214 4
2 2.000000 3
3 1.414214 5
4 1.414214 5
5 1.414214 3
6 1.414214 9
7 1.000000 10
8 1.414214 11
9 1.414214 11
10 2.000000 11
11 1.414214 9
Saya tidak menghitung ulang dan menguji ID, tetapi tampaknya setidaknya benar bahwa ID tersebut memang mengembalikan ID dari subgrup.
person
Willem Hendriks
schedule
14.12.2020
