我不知道如何NA
在Julia DataFrames中处理.
例如,使用以下DataFrame:
> import DataFrames
> a = DataFrames.@data([1, 2, 3, 4, 5]);
> b = DataFrames.@data([3, 4, 5, 6, NA]);
> ndf = DataFrames.DataFrame(a=a, b=b)
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我可以在列上成功执行以下操作 :a
> ndf[ndf[:a] .== 4, :]
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但如果我尝试相同的操作,:b
我会收到错误NAException("cannot index an array with a DataArray containing NA values")
.
> ndf[ndf[:b] .== 4, :]
NAException("cannot index an array with a DataArray containing NA values")
while loading In[108], in expression starting on line 1
in to_index at /Users/abisen/.julia/v0.3/DataArrays/src/indexing.jl:85
in getindex …
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