Manipulating Eq expressions

[bsdz]

Hi

Given an expression like Eq(a/b,c), how can I manipulate both lhs and rhs together? It would be useful if something like b*Eq(a/b,c) can become Eq(a,b*c).

Thanks 

Blair

[Shekhar Prasad Rajak]

You can do this : 

```

In [7]:  cancel(y*(x/y)-z)

Out[7]: x - z

```

--

Shekhar

[bsdz]

But that doesn't work with Eq. Also how would that work if I wish to do ln(Eq(a*b,c))? Converting the expression to form lhs-rhs wouldn't work.

[Shekhar Prasad Rajak]

Convert that into lhs - rhs form and try : 

In [39]: eq = Eq(x/y,z).lhs - Eq(x/y, z).rhs

In [40]: eq

Out[40]: 

x    

─ - z

y    

[bsdz]

Not quite what I'm asking but thanks anyhow :)

[Chris Smith]

This has been discussed from time to time. Basically you have to roll your own:

```

>>> e=Eq(x,y)

>>> e

Eq(x, y)

>>> do=lambda e,g: e.func(g(e.lhs),g(e.rhs))

>>> do(e,lambda _:_*3)

Eq(3*x, 3*y)

>>> do(_,lambda _:_/3)

Eq(x, y)

```

[Aaron Meurer]

See this issue https://github.com/sympy/sympy/issues/5031

Aaron Meurer

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