如何在ipython-notebook中获取sympy表达式的乳胶表? [英] How to get a latex table of sympy expressions in ipython-notebook?

问题描述

我正在使用sympy从多个表达式中收集术语，并希望将结果的格式(在ipython-notebook中)格式化为表格，其中术语位于最左侧一列，随后的每一列代表一个表达式.列中的条目来自sympy.collect(syms, evaluate=False)

I'm using sympy to collect terms from several expressions and would like to format the results (within ipython-notebook) in a table with the terms down the left most column and each subsequent column representing one expression. The entries in the column are from the dict returned by sympy.collect(syms, evaluate=False)

到目前为止，我有:

from IPython.display import display, Latex
import pandas as pd
import sympy as sym
sym.init_printing()
x,y,z = sym.symbols('x,y,z')
da,db,dc = sym.symbols('{\Delta}a {\Delta}b {\Delta}c ' )

e_list = []
d_list = []
e_list.append(da*2*x + da*(y - 2) + db*3*z + dc*(x+y))
e_list.append(dc*z + dc*x + da*x + db*(z+2))
for e in e_list:
    display(e.expand().collect((x,y,z)))
    d_list.append(e.expand().collect((x,y,z),evaluate=False))

df = pd.DataFrame(d_list).T

数据帧显示为我想要的，除了条目位于原始乳胶中.

The dataframe displays as I would like except the entries are in raw latex.

我可以执行以下操作:

Latex(df.to_latex())

但是我所得到的只是一个被盒子包围的乳胶代码.

but all I get is the latex code surrounded by a box.

这似乎是ipython和Latex表的已知问题，请参见此处:

This seems to be a known problem with ipython and latex tables, see here:

我有两种不同的解决方法. 使用unicode:

I've got two different workarounds. Use unicode:

sym.init_printing(use_latex=False)
...
da,db,dc = sym.symbols('∆a ∆b ∆c' )

或将表格显示为sympy矩阵:

Or display the table as a sympy matrix:

terms = [x,y,z]
d_list = [(e.expand().collect((terms),evaluate=False)) for e in e_list]
mterms = sym.zeros(M.shape[0],len(terms)+1)
key1 = d_list[0].keys()[0]
terms.insert(0,key1)
for i in range(mterms.shape[0]):
    for j in range(mterms.shape[1]):
        try:
            mterms[i,j] = d_list[i][terms[j]]
        except:
            mterms[i,j] = 0

mterms

推荐答案

毫无疑问，部分问题是您从df.to_latex()中获得的乳胶实际上不是有效的乳胶.例如，如果仅获取该函数的输出并将其粘贴到专用的乳胶文档中，它将无法编译.

Undoubtedly, part of the problem is that the latex you get out of df.to_latex() is not actually valid latex. For example, if you just take the output of that function and paste it into a dedicated latex document, it won't compile.

特别是，表中的某些条目包含诸如\Delta之类的内容，但它们在数学环境之外(没有美元符号).

In particular, some of the entries in the table contain things like \Delta, but these are outside of a math environment (no dollar signs).

所以这绝对是一个问题.另一个可能的问题是使用\toprule等.它们是非标准的乳胶结构(尽管它们可以与正确的乳胶包装一起使用)，但是我不知道这些rule是否被<识别. c6>函数.

So that's definitely a problem. Another possible problem is the use of \toprule, etc. Those are non-standard latex constructions (though they can be used with the right latex package), but I don't know if those rules are recognized by the Latex function.

所有这些都说明，我什至无法获得最简单的tabular环境来正确显示.例如，即使我这样做

All of that said, I can't even get the simplest tabular environment to display properly. For example, even if I do

Latex(r"""\begin{tabular}{l} 1 \\ 2 \end{tabular}""")

正如您所说，我得到了盒装结果. (尽管该字符串的内容确实可以在专用的乳胶文档中正确编译.)

I get a boxed result, just as you say. (Though the contents of that string do compile properly in a dedicated latex document.)

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