# [Python-ideas] Visually confusable unicode characters in identifiers

Georg Brandl g.brandl at gmx.net
Mon Oct 1 23:54:04 CEST 2012

```On 10/01/2012 10:51 PM, Guido van Rossum wrote:
> On Mon, Oct 1, 2012 at 1:26 PM, Oscar Benjamin
>> Non-ascii identifiers have other possible uses. I'll repost the case
>> that started this discussion on python-tutor (attached in case it
>> doesn't display):

Very nice!

>> '''
>> #!/usr/bin/env python3
>> # -*- encoding: utf-8 -*-
>>
>> # Parameters
>> α = 1
>> β = 0.1
>> γ = 1.5
>> δ = 0.075
>>
>> # Initial conditions
>> xₒ = 10
>> yₒ = 5
>> Zₒ = xₒ, yₒ
>>
>> # Solution parameters
>> tₒ = 0
>> Δt = 0.001
>> T = 10
>>
>> # Lotka-Volterra derivative
>> def f(Z, t):
>>     x, y = Z
>>     ẋ = x * (α - β*y)
>>     ẏ = -y * (γ - δ*x)
>>     return ẋ, ẏ
>>
>> # Accumulate results from Euler stepper
>> tᵢ = tₒ
>> Zᵢ = Zₒ
>> Zₜ, t = [], []
>> while tᵢ <= tₒ + T:
>>     Zₜ.append(Zᵢ)
>>     t.append(tᵢ)
>>     Zᵢ = [Zᵢⱼ+ Δt*Żᵢⱼ for Zᵢⱼ, Żᵢⱼ in zip(Zᵢ, f(Zᵢ, tᵢ))]
>>     tᵢ += Δt
>>
>> # Output since I don't have plotting libraries in Python 3
>> print('t', 'x', 'y')
>> for tᵢ, (xᵢ, yᵢ) in zip(t, Zₜ):
>>     print(tᵢ, xᵢ, yᵢ)
>> '''
>
> Those examples would be a lot more compelling if there was an
> acceptable way to input those characters. Maybe we could support some
> kind of input method that enabled LaTeX style math notation as used by
> scientists for writing equations in papers?

With the right editor, of course, it's not a problem :)

(Emacs has a TeX input method with which I could type this example without
problems.)

Georg

```