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Update CSV.read docs about WeakRefString conversions #118

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Update CSV.read docs about WeakRefString conversions #118

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ac116b4
Update docs
nickeubank Nov 26, 2017
baec40d
Update WeakRefString to String conversion docs
nickeubank Dec 8, 2017
aa38fd5
Avoid mentioning df (as it's not necessarily obvious what it means)
nalimilan Dec 8, 2017
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2 changes: 1 addition & 1 deletion src/Source.jl
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Expand Up @@ -244,7 +244,7 @@ Keyword Arguments:
* `categorical::Bool=true`: read string column as a `CategoricalArray` ([ref](https://github.com/JuliaData/CategoricalArrays.jl)), as long as the % of unique values seen during type detection is less than 67%. This will dramatically reduce memory use in cases where the number of unique values is small.

Note by default, "string" or text columns will be parsed as the [`WeakRefString`](https://github.com/quinnj/WeakRefStrings.jl) type. This is a custom type that only stores a pointer to the actual byte data + the number of bytes.
To convert a `String` to a standard Julia string type, just call `string(::WeakRefString)`, this also works on an entire column.
To convert a string column `col` to a standard Julia `String` vector, use either `convert(Array{String}, col)` or `convert(Array{Union{String, Missing}}, col)`, depending on whether the column supports `missing` values.
Oftentimes, however, it can be convenient to work with `WeakRefStrings` depending on the ultimate use, such as transfering the data directly to another system and avoiding all the intermediate copying.

Example usage:
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