MethodError when trying to get a row from an Arrow Dataframe in Julia

I have a dataset that looks like this:

I am taking a CSV file, converting it to Parquet and then sending it to Arrow. There is a reason why I am doing it like this. My goal is to get access to the information in row "Algeria". This is my code:

df = CSV.read("temp.csv", DataFrame)  write_parquet("data_file.parquet", df)  df = DataFrame(read_parquet("data_file.parquet"))  Arrow.write("data_file.arrow", df)  df = DataFrame(Arrow.Table("data_file.arrow"))    dates = names(df)[5:end]  countries = unique(df[:, :"Country/Region"])    algeria = df[df."Country/Region" .== "Algeria", 4:end]  # Print(sum(eachcol(algeria)))  Print(Statistics.mean(eachcol(algeria)))  

But the last part, which tries to retrieve the data from Arrow, throws this error:

MethodError: no method matching +(::Float64, ::String)    Closest candidates are:    +(::Any, ::Any, !Matched::Any, !Matched::Any...) at operators.jl:538    +(::Float64, !Matched::Float64) at float.jl:401    +(!Matched::ChainRulesCore.One, ::Any) at /home/onur/.julia/packages/ChainRulesCore/7d1hl/src/differential_arithmetic.jl:94  

What am I doing wrong?

This is what I get when I type in "Algeria" to the REPL

https://stackoverflow.com/questions/66681491/methoderror-when-trying-to-get-a-row-from-an-arrow-dataframe-in-julia March 18, 2021 at 05:26AM