# [ANN] PrettyNumbers.jl

Hi!

Long time, no see I am passing through a very big change, I was pretty much off-line in the previous months.

I just want to announce a very simple package called PrettyNumbers.jl. The idea is to format numbers in many back-ends (text, HTML, LaTeX, etc.), allowing, for example, to change the decimal base easily. Currently, only the text back-end exists.

julia> pretty_number(19//86)
¹⁹/₈₆

julia> pretty_number(19//86; compact = false)
19
——
86

julia> pretty_number(1906.1896)
1.90619 · 10³

julia> pretty_number(1906.1896, significand_format = "%.10f")
1.9061896000 · 10³

julia> pretty_number(1906.1896; new_decimal_base = 4)
0.190619 · 10⁴


I create this package to help me constructing reports when designing space missions like this one:

Depending on the size of the satellite, you want to see the results in a different unit (10^-3 Nm, or 10^-5 Nm, and so on). Hence, with PrettyNumbers.jl I can now do this very easily by just using a keyword argument in the function.

58 Likes

Very nice, thanks for the contribution.

Just a minor formatting comment. Let me cite here the section 7.3.3 Multiplication and division from “ISO 80000-1:2009/Cor 1:2011 Quantities and Units — Part 1: General — Technical Corrigendum 1.” ISO, October 2011. ISO - ISO 80000-1:2009/Cor 1:2011 - Quantities and units — Part 1: General — Technical Corrigendum 1 :

If the point is used as the decimal sign, the cross and not the half-high dot should be used as the multiplication sign between numbers expressed with digits. If the comma is used as the decimal sign, both the cross and the half-high dot may be used as the multiplication sign between numbers expressed with digits.

Perhaps having at least an option of this

julia> pretty_number(1906.1896)
1.90619 × 10³


will be great. If not even having this format as default.

14 Likes

Thanks for the information! I will definitely implement this feature Maybe we can have an option but use the X as the default.

9 Likes

I am a simple man.
I see a package by @Ronis_B, it gets added to my startup.jl.

Awesome tool and glad to see you around again!

7 Likes

Thanks!! I am glad they are being useful for you!

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@Ronis_BR, how would you do pretty_matrix() ?

A preliminary attempt combining your two awesome packages:

using PrettyNumbers, PrettyTables
pretty_matrix(M) = pretty_table(pretty_number.(String, M), noheader=true, tf=tf_borderless, alignment=:c)
M = Any[0.001 2e5; 19//86 -1e-3]
pretty_matrix(M)
# result:
1 ⋅ 10⁻³    2 ⋅ 10⁵
¹⁹/₈₆     -1 ⋅ 10⁻³


On a side note, how to keep π pretty?

pretty_number(π)  # result: 3.14159


Grato

4 Likes

This proposal is more or less what I would do to pretty print a matrix. If you want something more “mathematical” but a little bit more verbose, you can use tf = tf_matrix:

┌                     ┐
│ 1 ⋅ 10⁻³   2 ⋅ 10⁵  │
│  ¹⁹/₈₆    -1 ⋅ 10⁻³ │
└                     ┘


Good point! This should be very easy. I just need to add a new renderer for Irrational{:π}. I will try

4 Likes

@zdenek_hurak done!

If you use the latest version (0.2.0) the default multiplication sign is \times but you can change using the keyword multiplication_sign.

@rafael.guerra

Using latest PrettyTables (due to a bug), I think most matrices can be rendered good enough using this:

julia> using PrettyNumbers, PrettyTables

julia> ft(v, i, j) = pretty_number(String, v);

julia> pretty_matrix(M) = pretty_table(
M;
formatters = ft,
alignment_anchor_regex = Dict(0 => [r"\.", r"/"]),
alignment = :c,
alignment_anchor_fallback = :r,
tf = tf_matrix
);

julia> M = hcat([(randn())^i for i = -5:5 ], [rand(Any[π, ℯ, randn() * 100]) for i = 0:10], [rand(0:50)//rand(0:50) for i = 0:10]);

julia> pretty_matrix(M)
┌                                        ┐
│  1.20536 × 10³    π               ⁸/₄₁ │
│  5.51494 × 10²    ℯ              ⁴¹/₁₇ │
│ -4.43545 × 10⁻¹   π               ⁷/₆  │
│  4.77558 × 10⁻¹   π              ³⁷/₂₁ │
│  9.69893          5.99425 × 10¹  ⁴⁸/₁₇ │
│  1                ℯ              ⁴⁶/₃₃ │
│ -1.5696           π               ⁷/₃  │
│  1.89858          π               ⁷/₃₉ │
│ -5.55123 × 10⁻²   ℯ              ³⁸/₄₅ │
│  1.95432 × 10⁻¹  -7.89276 × 10¹   ³/₇  │
│ -1.57892 × 10⁻³  -9.1711 × 10¹   ⁴⁸/₅  │
└                                        ┘

5 Likes

I assume that e in the matrix stands for the Euler’s number. Then I cannot help bothering you once again with a reference to (another) standard: ISO - ISO 80000-2:2019 - Quantities and units — Part 2: Mathematics. In section 3 it reads

2 Likes

That is the Julia default:

help?> ℯ
"ℯ" can be typed by \euler<tab>

2 Likes

I see. Then… I don’t know

Yes! It used to be just e, I think, but changed at some point.

1 Like

Here’s the old discussion of this.

It looks like Julia adopted the unicode character which is recommended as the natural exponent. And that’s inconsistent with the ISO standard. From https://unicode.org/charts/PDF/U2100.pdf :

212F ℯ SCRIPT SMALL E
= error
= natural exponent
≈ 0065 e latin small letter e

5 Likes