pandas 如何在 IPython Notebook 中正确渲染数学表
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How to Render Math Table Properly in IPython Notebook
提问by Titanic
The math problem that I'm solving gives different analytical solutions in different scenarios, and I would like to summarize the result in a nice table. IPython Notebook renders the list nicely: for example:
我正在解决的数学问题在不同的场景下给出了不同的解析解，我想用一个漂亮的表格来总结结果。IPython Notebook 可以很好地呈现列表：例如：
import sympy
from pandas import DataFrame
from sympy import *
init_printing()
a, b, c, d = symbols('a b c d')
t = [[a/b, b/a], [c/d, d/c]]
t
However, when I summarize the answers into a table using DataFrame, the math cannot be rendered any more:
但是，当我使用 DataFrame 将答案汇总到表格中时，数学无法再呈现：
df = DataFrame(t, index=['Situation 1', 'Situation 2'], columns=['Answer1','Answer2'])
df
"print df.to_latex()" also gives the same result. I also tried "print(latex(t))" but it gives this after compiling in LaTex, which is alright, but I still need to manually convert it to a table:
“print df.to_latex()”也给出了相同的结果。我也试过 "print(latex(t))" 但它在 LaTex 中编译后给出了这个，没关系，但我仍然需要手动将其转换为表格：
How should I use DataFrame properly in order to render the math properly? Or is there any other way to export the math result into a table in Latex? Thanks!
我应该如何正确使用 DataFrame 以正确呈现数学？或者有没有其他方法可以将数学结果导出到 Latex 中的表格中？谢谢！
Update: 01/25/14 Thanks again to @Jakob for solving the problem. It works perfectly for simple matrices, though there are still some minor problems for more complicated math expressions. But I guess like @asmeurer said, perfection requires an update in IPython and Pandas.
更新：01/25/14 再次感谢@Jakob 解决了这个问题。它适用于简单的矩阵，但对于更复杂的数学表达式仍然存在一些小问题。但我想就像@asmeurer 所说的，完美需要 IPython 和 Pandas 的更新。
Update: 01/26/14
If I render the result directly, i.e. just print the list, it works fine:
更新：01/26/14 如果我直接渲染结果，即只打印列表，它工作正常：
采纳答案by Jakob
MathJax is currently not able to render tables, hence the most obvious approach (pure latex) does not work.
MathJax 目前无法渲染表格，因此最明显的方法（纯乳胶）不起作用。
However, following the advise of @asmeurer you should use an html table and render the cell content as latex. In your case this could be easily achieved by the following intermediate step:
但是，按照@asmeurer 的建议，您应该使用 html 表格并将单元格内容呈现为乳胶。在您的情况下，这可以通过以下中间步骤轻松实现：
from sympy import latex
tl = map(lambda tc: '$'+latex(tc)+'$',t)
df = DataFrame(tl, index=['Situation 1', 'Situation 2'], columns=['Answer'])
df
which gives:
这使：
Update:
更新：
In case of two dimensional data, the simple map function will not work directly. To cope with this situation the numpy shape, reshapeand ravelfunctions could be used like:
在二维数据的情况下，简单的地图功能将无法直接工作。为了应对这种情况，可以使用numpy shape、reshape和ravel函数，例如：
import numpy as np
t = [[a/b, b/a],[a*a,b*b]]
tl=np.reshape(map(lambda tc: '$'+latex(tc)+'$',np.ravel(t)),np.shape(t))
df = DataFrame(tl, index=['Situation 1', 'Situation 2'], columns=['Answer 1','Answer 2'])
df
This gives:
这给出：
Update 2:
更新 2：
Pandas crops cell content if the string length exceeds a certain number. E.g a more complicated expression like
如果字符串长度超过某个数字，Pandas 会裁剪单元格内容。例如更复杂的表达式，如
t1 = [a/2+b/2+c/2+d/2]
tl=np.reshape(map(lambda tc: '$'+latex(tc)+'$',np.ravel(t1)),np.shape(t1))
df = DataFrame(tl, index=['Situation 1'], columns=['Answer 1'])
df
gives:
给出：
To cope with this issue a pandas package option has to be altered, for details see here. For the present case the max_colwidthhas to be changed. The default value is 50, hence let's change it to 100:
为了解决这个问题，必须更改一个 pandas 包选项，有关详细信息，请参见此处。对于目前的情况max_colwidth，必须更改。默认值为 50，因此让我们将其更改为 100：
import pandas as pd
pd.options.display.max_colwidth=100
df
gives:
给出：
