JuliaData/CSV.jl

Add a types header

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#380 opened on Jan 26, 2019

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 (8 comments) (2 reactions) (0 assignees)Julia (119 forks)batch import
help wantednew feature

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Description

It'd be nice if you could tell CSV to write a types header line that would make it easier to read back into julia.

a,b,c,d
DateTime,String,Float64,MyType
...

Reading a value back could just always be parse(eval(Symbol(col_type)), x). The eval isn't great, but it's restricted to only symbols.

This approach would put the onus on package developers to appropriately define parse methods for their types, rather than the person loading the CSV.

Contributor guide

Research direction
Investigate the current CSV writing functionality in CSV.jl to understand how headers are written. Implement a new keyword argument (e.g., `types header=true`) that writes an additional header line with column types inferred from data or provided explicitly. Consider using `parse` and `eval` as suggested, but also evaluate type stability. Test with various data types like DateTime, String, Float64, and custom types.
Tech stack
julia
Domain
data
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JuliaCSV.jl
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70