# Saving Unitful DataFrame to file
**URL:** https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313
**Category:** Data
**Tags:** dataframes, unitful
**Created:** [October 6, 2021, 3:58pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313 "2021-10-06T15:58:09Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)
#### Post date: [October 6, 2021, 3:58pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/1 "2021-10-06T15:58:09Z")
Imagine I have a DataFrame with some of the columns being Unitful. Is there a way to save such a DataFrame into a file while preserving the information about the units?
The only solution I can think about is to strip it off units and save it to a .csv file. Then, when I load the file, I will have to multiply the columns by units.
But may be there is a good established approach to this?
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### Author:  [@DrPapa](https://discourse.julialang.org/u/DrPapa)
#### Post date: [October 6, 2021, 4:05pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/2 "2021-10-06T16:05:44Z")
Does it need to be human readable? If not , `Serialization.serialize` works out of the box for DataFrames + Unitful. [Serialization · The Julia Language](https://docs.julialang.org/en/v1/stdlib/Serialization/#Serialization.serialize)
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### Author:  [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)
#### Post date: [October 6, 2021, 4:15pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/3 "2021-10-06T16:15:23Z")
No, it does not have to be human readable, but I would like loading the file to be fast.
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### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [October 6, 2021, 4:20pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/4 "2021-10-06T16:20:30Z")
serialization is pretty good then
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### Author:  [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)
#### Post date: [October 6, 2021, 4:23pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/5 "2021-10-06T16:23:06Z")
By the way, does saving to .jld2 works as well?
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### Author:  [@DrPapa](https://discourse.julialang.org/u/DrPapa)
#### Post date: [October 6, 2021, 6:15pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/6 "2021-10-06T18:15:15Z")
I remember trying various serialization solutions and found Serialization to work best in terms of speed and serializing custom structs. Plus its a standard lib, which is a plus
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### Author:  [@DrPapa](https://discourse.julialang.org/u/DrPapa)
#### Post date: [October 6, 2021, 6:22pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/7 "2021-10-06T18:22:13Z")
For reference, a 450MB serialized dataframe file takes 109 ms to deserialize using Serialization.
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### Author:  [@Raf](https://discourse.julialang.org/u/Raf)
#### Post date: [October 6, 2021, 6:45pm UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/8 "2021-10-06T18:45:51Z")
Everyone wants this (for the repl and e.g. writing to csv):
[https://github.com/PainterQubits/Unitful.jl/issues/412](https://github.com/PainterQubits/Unitful.jl/issues/412)
[https://github.com/PainterQubits/Unitful.jl/issues/388](https://github.com/PainterQubits/Unitful.jl/issues/388)
[https://github.com/PainterQubits/Unitful.jl/pull/298](https://github.com/PainterQubits/Unitful.jl/pull/298)
[https://github.com/PainterQubits/Unitful.jl/issues/391](https://github.com/PainterQubits/Unitful.jl/issues/391)
[https://github.com/PainterQubits/Unitful.jl/issues/466](https://github.com/PainterQubits/Unitful.jl/issues/466)
There is a PR too:
[https://github.com/PainterQubits/Unitful.jl/pull/470](https://github.com/PainterQubits/Unitful.jl/pull/470)
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### Author:  [@phlavenk](https://discourse.julialang.org/u/phlavenk)
#### Post date: [February 10, 2023, 7:08am UTC](https://discourse.julialang.org/t/saving-unitful-dataframe-to-file/69313/9 "2023-02-10T07:08:03Z")
There is a package for **reversible** converting :
[UnitfulParsableString.jl](https://github.com/michikawa07/UnitfulParsableString.jl)
I’m using these functions for Arrows saving using that package:
```julia
function deunitful(df::AbstractDataFrame)
for colname in names(df)
col = df[!,colname]
firstval = skipmissing(col)[1]
if firstval isa Number
ustr = string(Unitful.unit(firstval))
df[!,colname] .= ustrip.(df[!,colname])
colmetadata!(df, colname, "units", ustr, style=:note);
colmetadata(df, colname, "units")
end
end
df
end
function reunitful(df::AbstractDataFrame)
for colname in names(df)
if "units" in colmetadatakeys(df, colname)
ustr = colmetadata(df, colname, "units")
un = Unitful.uparse(ustr)
df[!,colname] .= df[!,colname] .* un
deletecolmetadata!(df, colname, "units")
end
end
df
end
```