使用熊猫的欧几里德距离矩阵

时间:2016-08-29 10:08:57

标签: python pandas dataframe

我有一个.csv文件,其中包含以下格式的城市,纬度和经度数据:

CITY|LATITUDE|LONGITUDE
A|40.745392|-73.978364
B|42.562786|-114.460503
C|37.227928|-77.401924
D|41.245708|-75.881241
E|41.308273|-72.927887

我需要以下面的格式创建一个距离矩阵(请忽略虚拟值):

         A         B         C         D         E   
A  0.000000  6.000000  5.744563  6.082763  5.656854  
B  6.000000  0.000000  6.082763  5.385165  5.477226  
C  1.744563  6.082763  0.000000  6.000000  5.385165
D  6.082763  5.385165  6.000000  0.000000  5.385165  
E  5.656854  5.477226  5.385165  5.385165  0.000000  

我已将数据加载到pandas数据框中,并创建了一个交叉连接,如下所示:

import pandas as pd
df_A = pd.read_csv('lat_lon.csv', delimiter='|', encoding="utf-8-sig")
df_B = df_A
df_A['key'] = 1
df_B['key'] = 1 
df_C = pd.merge(df_A, df_B, on='key')  
  • 能帮我创建上面的矩阵结构吗?
  • 另外,是否可以避免涉及交叉连接的步骤?

3 个答案:

答案 0 :(得分:9)

您可以使用pdist中的squareformscipy.spatial.distance方法:

In [12]: df
Out[12]:
  CITY   LATITUDE   LONGITUDE
0    A  40.745392  -73.978364
1    B  42.562786 -114.460503
2    C  37.227928  -77.401924
3    D  41.245708  -75.881241
4    E  41.308273  -72.927887

In [13]: from scipy.spatial.distance import squareform, pdist

In [14]: pd.DataFrame(squareform(pdist(df.iloc[:, 1:])), columns=df.CITY.unique(), index=df.CITY.unique())
Out[14]:
           A          B          C          D          E
A   0.000000  40.522913   4.908494   1.967551   1.191779
B  40.522913   0.000000  37.440606  38.601738  41.551558
C   4.908494  37.440606   0.000000   4.295932   6.055264
D   1.967551  38.601738   4.295932   0.000000   2.954017
E   1.191779  41.551558   6.055264   2.954017   0.000000

答案 1 :(得分:0)

for i in df["CITY"]:
    for j in df["CITY"]:
        row = df[df["CITY"] == j][["LATITUDE", "LONGITUDE"]]
        latitude = row["LATITUDE"].tolist()[0]
        longitude = row["LONGITUDE"].tolist()[0]
        df.loc[df['CITY'] == i, j] = ((df["LATITUDE"] - latitude)**2 + (df["LONGITUDE"] - longitude)**2)**0.5

df = df.drop(["CITY", "LATITUDE", "LONGITUDE"], axis=1)

这有效

答案 2 :(得分:0)

可以使用cdist中的scipy.spatial.distance直接创建矩阵:

from scipy.spatial.distance import cdist
df_array = df[["LATITUDE", "LONGITUDE"]].to_numpy()
dist_mat = cdist(df_array, df_array)
pd.DataFrame(dist_mat, columns = df["CITY"], index = df["CITY"])