NCDataFrame.jl

Read & write NetCDF file via DataFrames.

Manual

Install

using Pkg

Pkg.add("NCDataFrame")

Read

using NCDataFrame

df = readnc("data.nc") # DataFrame

Write

using NCDataFrame
using DataFrames

df = DataFrame()
df[!,:x] = 1:10
df[!,:y] = 'a':'j'

writenc(df, "data.nc")

Fill missing

fillmissing(1:3, 5)         # [1,2,3,missing,missing]
fillmissing([1,2,3], 5)     # [1,2,3,missing,missing]
fillmissing(1:5, 5)         # 1:5
fillmissing([1,2,3,4,5], 5) # [1,2,3,4,5]

Tips for different length vectors

using NCDataFrame
using DataFrames

df = DataFrame()
df[!, :x] = fillmissing(1:3, 5)     # [1,2,3,missing,missing]
df[!, :y] = 1:5                     # [1,2,3,4,5]

writenc(df, "data.nc")              # It works!

dg = readnc("data.nc")              # It works too!
dg[!,:x] |> skipmissing |> collect  # Remove missing from x

Trouble Shooting

Error on install NCDatasets

For error message such as :

ERROR: LoadError: InitError: could not load library "$HOME/.julia/artifacts/0a7f440ba143b238cc3dd0def2956d34d76755f3/lib/libnetcdf.so"

You can solve it by following procedures.

1. Install libnetcdf
2. cd $HOME/.julia/artifacts/0a7f440ba143b238cc3dd0def2956d34d76755f3/lib/
3. unlink libnetcdf.so
4. unlink libnetcdf.so.18
5. ln -s /usr/lib/libnetcdf.so $PWD/libnetcdf.so
6. ln -s /usr/lib/libnetcdf.so.18 $PWD/libnetcdf.so.18
7. In julia, using NCDataFrame than finish!

References

NCDataFrame.jl uses below packages inside.

• DataFrames.jl
• NCDatasets.jl
• Missings.jl