CODEWITHSUNDEEP
pythonipythonsympyjupyter-notebook
Yuri F Becker
Yuri F Becker

Reputation: 368

Custom printing in jupyter notebook

I'm looking for an alternative to MathCad to make simple calculations but I wanted the expressions to look like if I was using pen and paper and make it easy to read for people who don't know programming. I tried Sweave, Knitr but I was unhappy with it. I recently found Jupyter notebook with SymPy and it's still not as easy as MathCad for me, but I'll give it a try. With Jupyter I'm having trouble printing formulas: I want to print both sides of the equation automatically.

What I want:

enter image description here

What i get:

enter image description here

What I tried

ccode doesn't return latex and it's boring always typing "assign_to" enter image description here

Upvotes: 4

Views: 1244

Answers (3)

asmeurer
asmeurer

Reputation: 91480

You need to use sympy.Eq if you want to print an equation. The = operator just assigns variables in Python, meaning in your example, the Python variable R_r is assigned to the SymPy expression (c_1 + (c_2*x/G) + c_3*V)*G.

In general in Python, there is no reverse association with an object and the variable it is assigned to. There is no way for the expression to "know" that it is assigned to a variable named R_r.

Instead, you need to create a symbol named R_r and use Eq(R_r, (c_1 + (c_2*x/G) + c_3*V)*G).

See also http://docs.sympy.org/latest/tutorial/gotchas.html and http://nedbatchelder.com/text/names.html.

Upvotes: 2

Daewon Lee
Daewon Lee

Reputation: 630

If you need a more convenient way, you can define a wrapper function as follows.

class Equation(object):    
    def __init__(self, left, right, mode='latex'):        
        self.mode = mode
        self.left = left
        self.right = right

        self._eq = sym.Eq(left, right)
        self._latex = sym.latex(self._eq)

    def __repr__(self):
        if self.mode == 'latex':
            return self._latex.__repr__()
        elif self.mode == 'sympy':
            return self._eq.__repr__()

    def __str__(self):
        if self.mode == 'latex':
            return self._latex
        elif self.mode == 'sympy':
            return self.eq.__str__()

    def eq(self):
        return self._eq

    def latex(self):
        return self._latex

    @property
    def mode(self):
        return self._mode

    @mode.setter
    def mode(self, val):
        self._mode = val

    @property
    def left(self):
        return self._left
    @left.setter
    def left(self, val):
        self._left = sym

    @property
    def right(self):
        return self._right

    @right.setter
    def right(self, val):
        self._right = val
# end of class

enter image description here

Upvotes: 4

Daewon Lee
Daewon Lee

Reputation: 630

You can use sympy.printing.latex.

SymPy using LaTeX printing

Refer to the following link for more information.

http://docs.sympy.org/dev/modules/printing.html?highlight=sympy.printing#module-sympy.printing.latex

Upvotes: 0

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