# Converting CSV to Parquet in Julia
**URL:** https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328
**Category:** New to Julia
**Tags:** question, csv, parquet
**Created:** [March 16, 2021, 7:13pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328 "2021-03-16T19:13:10Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 7:13pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/1 "2021-03-16T19:13:10Z")
Hi.
I have a simple dataframe that I want to convert to parquet. This is my attempt:
```julia
begin
df = CSV.read("/home/onur/julia-assignment/temp.csv", DataFrame)
prq = Parquet.File(df)
end
```
But this is the error I’m getting:
```julia
MethodError: no method matching Parquet.File(::DataFrames.DataFrame)
Closest candidates are:
Parquet.File(::Any, !Matched::Any, !Matched::Any, !Matched::Any, !Matched::Any) at /home/onur/.julia/packages/Parquet/h8mm5/src/reader.jl:54
Parquet.File(!Matched::String, !Matched::IOStream, !Matched::Parquet.PAR2.FileMetaData, !Matched::Parquet.Schema, !Matched::Parquet.PageLRU) at /home/onur/.julia/packages/Parquet/h8mm5/src/reader.jl:54
Parquet.File(!Matched::AbstractString; map_logical_types) at /home/onur/.julia/packages/Parquet/h8mm5/src/reader.jl:61
```
How can I open a CSV file as Parquet?
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 7:31pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/2 "2021-03-16T19:31:58Z")
Judging by the [Parquet.jl README](https://github.com/JuliaIO/Parquet.jl/blob/master/README.md#writer) it should be
```julia
using CSV, Parquet
df = CSV.read("/home/onur/julia-assignment/temp.csv", DataFrame)
file = tempname() * ".parquet"
write_parquet(file, df)
```
or any other filename of your choice.
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 7:35pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/3 "2021-03-16T19:35:15Z")
And how can I view the file in Pluto like I would with Pandas in Jupyter?
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 7:40pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/4 "2021-03-16T19:40:20Z")
I am not sure I understand the question, sorry. `Parquet`, `CSV`, `Arrow` and so on, are just storage formats. I suppose it is possible to do something with the data representation, but this is usually something low level. It’s not the way how usually people are working with data. Roughly speaking, common way is to store in one or another format, then load it to memory and transform to a representation which is more suitable for data manipulation. After everything is done you store it again in necessary format.
Data representation which is convenient for various manipulations is pandas in python, dataframes in R, and DataFrame in Julia. But you already did it on the first step, when you loaded data from the CSV.
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 7:40pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/5 "2021-03-16T19:40:54Z")
Can I view the file in Pluto? Is there a way to do that? That’s what I am curious about.
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 7:43pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/6 "2021-03-16T19:43:06Z")
What is “viewing the file”? You can get it binary presentation with `read(file)`. Or, you can load it with `DataFrame(read_parquet(path))` but that should give you more or less the same `DataFrame` that you get on `CSV.read` step.
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 7:44pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/7 "2021-03-16T19:44:33Z")
Can I recreate the CSV file as Parquet in my working directory?
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:02pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/8 "2021-03-16T20:02:07Z")
This is the error I got
```julia
MethodError: no method matching read_parquet(::String, ::DataFrames.DataFrame)
```
---
### Author:  [@lungben](https://discourse.julialang.org/u/lungben)
#### Post date: [March 16, 2021, 8:15pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/9 "2021-03-16T20:15:40Z")
Just put the name of the DataFrame into a Pluto cell to view it in Pluto:
```julia
df
```
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:16pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/10 "2021-03-16T20:16:51Z")
Yea but how can I confirm if the output of `df` is now Parquet and not CSV, as it used to be?
---
### Author:  [@lungben](https://discourse.julialang.org/u/lungben)
#### Post date: [March 16, 2021, 8:18pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/11 "2021-03-16T20:18:52Z")
Viewing the DataFrame and writing to disk are completely separate topics.
CSV and Parquet are disk formats, DataFrames are in memory.
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:22pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/12 "2021-03-16T20:22:31Z")
Can I write this CSV file also as a Parquet file to my working directory? If so, how can I do that?
---
### Author:  [@lungben](https://discourse.julialang.org/u/lungben)
#### Post date: [March 16, 2021, 8:24pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/13 "2021-03-16T20:24:42Z")
Have you tried the method described by @Skoffer ?
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:25pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/14 "2021-03-16T20:25:55Z")
Yea. I don’t see a parquet file in my current directory.
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 8:31pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/15 "2021-03-16T20:31:00Z")
Just change `file` definition to
```julia
file = "/home/onur/julia-assignment/temp.parquet"
```
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:33pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/16 "2021-03-16T20:33:14Z")
Wait. Just changing the file extension automatically converts to parquet?
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 8:34pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/17 "2021-03-16T20:34:58Z")
Obviously not. Changing directory from `/tmp` (as it is produced by `tempfile`) to `/home/onur/julia-assignment’ changes location of the resulting file.
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:36pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/18 "2021-03-16T20:36:22Z")
> [@Skoffer](#):
>
> `parquet`
I get this
```julia
ArgumentError: "/home/onur/julia-assignment/temp.parquet" is not a valid file
```
---
### Author:  [@Skoffer](https://discourse.julialang.org/u/Skoffer)
#### Post date: [March 16, 2021, 8:37pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/19 "2021-03-16T20:37:52Z")
```julia
using CSV, Parquet
df = CSV.read("/home/onur/julia-assignment/temp.csv", DataFrame)
file = "/home/onur/julia-assignment/temp.parquet"
write_parquet(file, df)
```
Which line exactly giving you this error? Can you show the complete output?
---
### Author:  [@oo92](https://discourse.julialang.org/u/oo92)
#### Post date: [March 16, 2021, 8:39pm UTC](https://discourse.julialang.org/t/converting-csv-to-parquet-in-julia/57328/20 "2021-03-16T20:39:40Z")
> [@Skoffer](#):
>
> `file = "/home/onur/julia-assignment/temp.parquet"`
Nvm. I messed up on this line. It was my mistake. Thank you very much.
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