从所有排列的数据框创建一个矩阵答案

【问题标题】：Create a matrix from the dataframe of all permutations从所有排列的数据框创建一个矩阵
【发布时间】：2020-09-11 11:49:40
【问题描述】：

我有一个数据框，包含加州火车 2 个车站的所有可能组合以及它们之间的行程票价。我想制作一个价值矩阵，但不明白如何。数据如下：


+=========================+=========================+========+
|       SOURCE_STN        |        DEST_STN         | RC1($) |
+=========================+=========================+========+
| 22nd Street             | Atherton                |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| 22nd Street             | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Blossom Hill            |  12.75 |
+-------------------------+-------------------------+--------+
| 22nd Street             | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| 22nd Street             | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Belmont                 |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Broadway                |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Bayshore                |   3.75 |
+-------------------------+-------------------------+--------+
| 22nd Street             | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| 22nd Street             | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+
| Atherton                | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| Atherton                | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| Atherton                | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| Atherton                | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Blossom Hill            |  12.75 |
+-------------------------+-------------------------+--------+
| Atherton                | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| Atherton                | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| Atherton                | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| Atherton                | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| Atherton                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | 22nd Street             |   3.75 |
+-------------------------+-------------------------+--------+
| Atherton                | Broadway                |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| Atherton                | Belmont                 |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| Atherton                | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| Atherton                | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| Atherton                | Bayshore                |   3.75 |
+-------------------------+-------------------------+--------+
| Atherton                | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| Atherton                | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+
| Bayshore                | Atherton                |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| Bayshore                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | 22nd Street             |   3.75 |
+-------------------------+-------------------------+--------+
| Bayshore                | Broadway                |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| Bayshore                | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| Bayshore                | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Blossom Hill            |  12.75 |
+-------------------------+-------------------------+--------+
| Bayshore                | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| Bayshore                | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| Bayshore                | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| Bayshore                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | Belmont                 |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| Bayshore                | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| Bayshore                | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| Bayshore                | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| Bayshore                | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | Atherton                |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| Belmont                 | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | 22nd Street             |   3.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | Broadway                |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| Belmont                 | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| Belmont                 | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Blossom Hill            |  12.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| Belmont                 | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| Belmont                 | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| Belmont                 | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| Belmont                 | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| Belmont                 | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | Bayshore                |   3.75 |
+-------------------------+-------------------------+--------+
| Belmont                 | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| Belmont                 | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Atherton                |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | 22nd Street             |   3.75 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Broadway                |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Belmont                 |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Bayshore                |   3.75 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| Blossom Hill            | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+
| Broadway                | Atherton                |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Redwood City            |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Millbrae Transit Center |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Stanford                |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Santa Clara             |   10.5 |
+-------------------------+-------------------------+--------+
| Broadway                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | 22nd Street             |   3.75 |
+-------------------------+-------------------------+--------+
| Broadway                | Sunnyvale               |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | San Martin              |     15 |
+-------------------------+-------------------------+--------+
| Broadway                | California Ave.         |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Tamien                  |   10.5 |
+-------------------------+-------------------------+--------+
| Broadway                | Lawrence                |   10.5 |
+-------------------------+-------------------------+--------+
| Broadway                | San Antonio             |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Burlingame              |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | San Mateo               |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Hayward Park            |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Blossom Hill            |  12.75 |
+-------------------------+-------------------------+--------+
| Broadway                | South San Francisco     |   3.75 |
+-------------------------+-------------------------+--------+
| Broadway                | San Carlos              |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | San Jose Diridon        |   10.5 |
+-------------------------+-------------------------+--------+
| Broadway                | Gilroy                  |     15 |
+-------------------------+-------------------------+--------+
| Broadway                | College Park            |   10.5 |
+-------------------------+-------------------------+--------+
| Broadway                | Menlo Park              |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Palo Alto               |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | Morgan Hill             |     15 |
+-------------------------+-------------------------+--------+
| Broadway                | Belmont                 |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Hillsdale               |      6 |
+-------------------------+-------------------------+--------+
| Broadway                | Capitol                 |  12.75 |
+-------------------------+-------------------------+--------+
| Broadway                | Bayshore                |   3.75 |
+-------------------------+-------------------------+--------+
| Broadway                | Mountain View           |   8.25 |
+-------------------------+-------------------------+--------+
| Broadway                | San Francisco           |   3.75 |
+-------------------------+-------------------------+--------+

我试图用 pd.Dataframe(index = , columns =) 做一些事情，但它不起作用。应该是这样的：


+---------------+----------------+-----------+
|    station    |  San Francisco |  Broadway |
+---------------+----------------+-----------+
| San Francisco |  0             |  value    |
| Broadway      | value          |  0        |
+---------------+----------------+-----------+

谢谢！

【问题讨论】：

标签： python numpy dataframe matrix

【解决方案1】：

您需要使用df.pivot()。

df.pivot(index='SOURCE_STN', columns='DEST_STN', values='RC1($)').fillna(0)

编辑：
对于具有重复的数据框，您需要改用df.pivot_table() 并在aggfunc 参数中指定聚合函数。

import numpy as np

df.pivot_table(index='SOURCE_STN', columns='DEST_STN', values='RC1($)', aggfunc=np.sum).fillna(0)

【讨论】：

糟糕，由于源和目标中的重复站，它不起作用，因为我有排列。
也不行，有的车站组合票价大于最大票价，有的车站到各车站票价相同。这是数据的链接：docs.google.com/spreadsheets/d/…
@ZheniaMagic 我不明白：为什么会有重复？除了从车站到它自己还有什么？
@IgorRivin 有重复，因为我有 32 个站点，数据帧基本上都是它们的 993 个排列。所以所有可能的电台对。
@ZheniaMagic 但是SOURCE_STN, DEST_STN 组合如果有意义的话就不应该有重复。

【解决方案2】：

您可以通过在 pandas 中使用 pivot_table 来实现此目的。

data_frame.pivot_table('RC1($)', 'SOURCE_STN', 'DEST_STN').fillna(0)

说明：

您期望的矩阵可以通过以下代码实现，因为排列仍然保留，同时还通过获取重复项的平均值来管理重复项。

import pandas as pd
import numpy as np

route_table = pd.read_csv("path_to_file.csv")

route_matrix = route_table.pivot_table('RC1($)', 'SOURCE_STN', 'DEST_STN', aggfunc=np.mean).fillna(0)
print(route_matrix)

输出：

DEST_STN                 22nd Street  Atherton  ...  Sunnyvale  Tamien
SOURCE_STN                                      ...                   
22nd Street                     0.00      8.25  ...       8.25    10.5
Atherton                        3.75      0.00  ...       8.25    10.5
Bayshore                        3.75      8.25  ...       8.25    10.5
Belmont                         3.75      8.25  ...       8.25    10.5
Blossom Hill                    3.75      8.25  ...       8.25    10.5
Broadway                        3.75      8.25  ...       8.25    10.5
Burlingame                      3.75      8.25  ...       8.25    10.5
California Ave.                 3.75      8.25  ...       8.25    10.5
Capitol                         3.75      8.25  ...       8.25    10.5
College Park                    3.75      8.25  ...       8.25    10.5
Gilroy                          3.75      8.25  ...       8.25    10.5
Hillsdale                       3.75      8.25  ...       8.25    10.5

为了更好地理解透视表的不同视角：

备用代码

route_matrix = route_table.pivot_table('RC1($)', 'DEST_STN', 'SOURCE_STN', aggfunc=np.mean).fillna(0)
print(route_matrix)

输出

SOURCE_STN               22nd Street  Atherton  ...  Sunnyvale  Tamien
DEST_STN                                        ...                   
22nd Street                     0.00      3.75  ...       3.75    3.75
Atherton                        8.25      0.00  ...       8.25    8.25
Bayshore                        3.75      3.75  ...       3.75    3.75
Belmont                         6.00      6.00  ...       6.00    6.00
Blossom Hill                   12.75     12.75  ...      12.75   12.75
Broadway                        6.00      6.00  ...       6.00    6.00
Burlingame                      6.00      6.00  ...       6.00    6.00
California Ave.                 8.25      8.25  ...       8.25    8.25
Capitol                        12.75     12.75  ...      12.75   12.75
College Park                   10.50     10.50  ...      10.50   10.50
Gilroy                         15.00     15.00  ...      15.00   15.00

【讨论】：

由于重复值，此答案也不起作用。
我实现你的代码后，从一站到每一站的票价都是一样的...
@ZheniaMagic 我认为这个答案应该适合您的情况。