JuliaLang/julia

function to change numeric output format

Open

#6,493 opened on Apr 10, 2014

View on GitHub
 (24 comments) (0 reactions) (0 assignees)Julia (5,773 forks)batch import
REPLdisplay and printinggood first issue

Repository metrics

Stars
 (48,709 stars)
PR merge metrics
 (Avg merge 20d 6h) (157 merged PRs in 30d)

Description

I want change output format for numbers (stand alone floats, float matrix, BigFloats). I can do it in IPython by using %precision magic function. I didn't find any equivalent in Julia.

I know that I can use round but it actually returns different number. It's also cumbersome to convert arrays with combination map + round. One another problem: I didn't get how to change real or output precision of BigFloat: set_bigfloat_precision changes precision for all new BigFloats, copy and deepcopy don't help (they copy value irrespective of new default BigFloat precision), naive precision change via BigFloat.prec corrupts it.

I know, that I handle lot's of different topics in this question and I as a programmer understand that lot's of difficulties lays in output formats. But my friend, mathematician asked me: "Why can I just type %precision in my IPython notebook but not in Julia? Isn't output format change essential feature?".

Contributor guide

Research direction
Research how output formatting is handled in Julia's REPL, study the existing `show` methods for numeric types, and consider implementing a command similar to `%precision` in IPython. Look at the `Base.show` and `Base.print` functions for floats and BigFloats.
Tech stack
julia
Domain
developer experience
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JuliaGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60