Unhelpful error with quantile!(x, q)

[JockLawrie]

Hi there,
When computing quantiles on DataArrays, if the DataArray contains an NA I get an error that could be more helpful. See example below.

using DataArrays

x = DataArray(Int64, 3)
x[1] = 1
x[2] = 2
x[3] = 3
quantile!(x, [0.5])    # OK, no problem

x[3] = NA
quantile!(x, [0.5])    # Unhelpful error

The error is:
ERROR: MethodError: isnan has no method matching isnan(::DataArrays.NAtype) in quantile! at statistics.jl:528

The source code of statistics.jl has the message "quantiles are undefined in presence of NaNs", which is more helpful. How can this message be shown rather than the one currently shown?

[nalimilan]

This is because the generic implementation for AbstractArray is used, instead of a specific method for DataArray. You could easily fix this by copying the general method, restricting its signature to DataArrays, and adding a check for isna before that for isnan.

(But these days, the development focus has moved towards NullableArrays.jl, which offers a much better performance and will eventually replace DataArrays.jl.)

[JockLawrie]

OK thanks. Given the current direction towards NullableArrays.jl I'm inclined to not put any effort into this issue. Feel free to close.