2D Numpy 数组到 HTML 表？

Question

这是我的 numpy 数组：

num = np.array([[ 0.17899619  0.33093259  0.2076353   0.06130814]
                [ 0.20392888  0.42653105  0.33325891  0.10473969]
                [ 0.17038247  0.19081956  0.10119709  0.09032416]
                [-0.10606583 -0.13680513 -0.13129103 -0.03684349]
                [ 0.20319428  0.28340985  0.20994867  0.11728491]
                [ 0.04396872  0.23703525  0.09359683  0.11486036]
                [ 0.27801304 -0.05769304 -0.06202813  0.04722761]])

这是我的标题行：

days = ['5 days', '10 days', '20 days', '60 days']

这是我的第一篇专栏：

prices = ['AAPL', 'ADBE', 'AMD', 'AMZN', 'CRM', 'EXPE', 'FB']

我想把它全部放在一个 HTML 表格中，如下所示：

<table border=1>
    <tr>
        <th>Prices</th><th>5 days</th><th>10 days</th><th>20 days</th><th>60 days</th>
    </tr>
    <tr>
        <td>APPL</td><td>0.17899619</td><td>0.33093259</td><td>0.2076353</td><td>0.06130814</td>
    </tr>
    <tr>
        <td>ADBE</td><td>0.20392888</td><td>0.42653105</td><td>0.33325891</td><td>0.10473969</td>
    </tr>
    <tr>
        <td>AMD</td><td>0.17038247</td><td>0.19081956</td><td>0.10119709</td><td>0.09032416</td>
    </tr>
    <tr>
        <td>AMZN</td><td>-0.10606583</td><td>-0.13680513</td><td>-0.13129103</td><td>-0.03684349</td>
    </tr>
    <tr>
        <td>CRM</td><td>0.20319428</td><td>0.28340985</td><td>0.20994867</td><td>0.11728491</td>
    </tr>
    <tr>
        <td>EXPE</td><td>0.04396872</td><td>0.23703525</td><td>0.09359683</td><td>0.11486036</td>
    </tr>
    <tr>
        <td>FB</td><td>0.27801304</td><td>-0.05769304</td><td>-0.06202813</td><td>0.04722761</td>
    </tr>
</table>

有没有pythonic方法可以做到这一点？或者有什么我可以使用的模块（在 Python 3 上）？

谢谢。

Answer 1

pandas DataFrame 有一个to_html 方法：

import numpy as np
import pandas as pd

num = np.array([[ 0.17899619,  0.33093259,  0.2076353,   0.06130814,],
                [ 0.20392888,  0.42653105,  0.33325891,  0.10473969,],
                [ 0.17038247,  0.19081956,  0.10119709,  0.09032416,],
                [-0.10606583, -0.13680513, -0.13129103, -0.03684349,],
                [ 0.20319428,  0.28340985,  0.20994867,  0.11728491,],
                [ 0.04396872,  0.23703525,  0.09359683,  0.11486036,],
                [ 0.27801304, -0.05769304, -0.06202813,  0.04722761,],])

days = ['5 days', '10 days', '20 days', '60 days']

prices = ['AAPL', 'ADBE', 'AMD', 'AMZN', 'CRM', 'EXPE', 'FB']

df = pd.DataFrame(num, index=prices, columns=days)

html = df.to_html()

print(html)

输出：

<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th></th>
      <th>5 days</th>
      <th>10 days</th>
      <th>20 days</th>
      <th>60 days</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th>AAPL</th>
      <td>0.178996</td>
      <td>0.330933</td>
      <td>0.207635</td>
      <td>0.061308</td>
    </tr>
    <tr>
      <th>ADBE</th>
      <td>0.203929</td>
      <td>0.426531</td>
      <td>0.333259</td>
      <td>0.104740</td>
    </tr>
    <tr>
      <th>AMD</th>
      <td>0.170382</td>
      <td>0.190820</td>
      <td>0.101197</td>
      <td>0.090324</td>
    </tr>
    <tr>
      <th>AMZN</th>
      <td>-0.106066</td>
      <td>-0.136805</td>
      <td>-0.131291</td>
      <td>-0.036843</td>
    </tr>
    <tr>
      <th>CRM</th>
      <td>0.203194</td>
      <td>0.283410</td>
      <td>0.209949</td>
      <td>0.117285</td>
    </tr>
    <tr>
      <th>EXPE</th>
      <td>0.043969</td>
      <td>0.237035</td>
      <td>0.093597</td>
      <td>0.114860</td>
    </tr>
    <tr>
      <th>FB</th>
      <td>0.278013</td>
      <td>-0.057693</td>
      <td>-0.062028</td>
      <td>0.047228</td>
    </tr>
  </tbody>
</table>

Answer 2

Jupyter 笔记本用户应该会发现这很有用。如果有人将其作为适当的模块实现，请在 cmets 中告诉我！

import numpy as np
from html import escape

class PrettyArray(np.ndarray):
    def _repr_html_(self):
        """Numpy array HTML representation function."""
        # Fallbacks for cases where we cannot format HTML tables
        if self.size > 10_000:
            return f"Large numpy array {self.shape} of {self.dtype}"
        if self.ndim != 2:
            return f"<pre>{escape(str(self))}</pre>"
        # Table format
        html = [f"<table><tr><th>{self.dtype}"]
        rows, columns = self.shape
        html += (f"<th>{j}" for j in range(columns))
        for i in range(rows):
            html.append(f"<tr><th>{i}")
            for j in range(columns):
                val = self[i, j]
                html.append("<td>")
                html.append(escape(f"{val:.2f}" if self.dtype == float else f"{val}"))
        html.append("</table>")
        return "".join(html)

我们使用 Numpy view 函数来启用这个接口：

np.array([[1, 2], [3, 4]]).view(PrettyArray)

诀窍在于这种类型很有效，只要您的一个数组设置了视图，结果将始终是 PrettyArray。例如，这仍然会打印第二行结果的 HTML 表格：

arr = np.random.normal(size=(4, 8)).view(PrettyArray)
np.eye(4) @ arr**2 @ np.eye(8)