# How to parse/convert integers in DataFrame to float numbers

**URL:** <https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507>\
**Category:** New to Julia\
**Tags:** dataframes\
**Created:** [March 19, 2021, 12:07am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507 "2021-03-19T00:07:05Z")\
**Posts on this page:** 11\
**Page:** 2

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**Author:** ![pdeffebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pdeffebach/32/10320_2.png) [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Post date:** [March 19, 2021, 1:57am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/21 "2021-03-19T01:57:38Z")

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You only “fixed” columns `4:end` in your loop. But are doing `eachcol` on all columns in your dataset.

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**Author:** ![pdeffebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pdeffebach/32/10320_2.png) [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Post date:** [March 19, 2021, 1:58am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/22 "2021-03-19T01:58:32Z")

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Are you sure? With DataFrames loaded, `passmissing` should be defined.

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**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [March 19, 2021, 1:58am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/23 "2021-03-19T01:58:56Z")

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not sure what is screwed up because it works for me, I will paste the complete example including downloading data below:

```julia
julia> using CSV, DataFrames

julia> df = DataFrame(CSV.File(download("https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_global.csv")))

julia> algeria = df[df."Country/Region" .== "Algeria", 4:end]

julia> unique(describe(algeria).eltype)
2-element Vector{Type}:
 Union{Missing, Float64}
 Int64

julia> for i = 1:size(algeria, 2)
              if eltype(algeria[!, i]) .!= Float64
                  algeria[!, i] = float.(algeria[!, i])
              end
         end

julia> unique(describe(algeria).eltype)
1-element Vector{DataType}:
 Float64

julia> algeria
1×422 DataFrame
 Row │ Long 1/22/20 1/23/20 1/24/20 1/25/20 1/26/20 1/27/20 1/28/20 1/29/20 1/30/20 1/31/20 2/1/20 2/2/20 2/3/20 2/4/20 2/5/20 2/6/20 2/7/20 2/8/20 2/9/20 2/10/20 2/11/20 2/12/20 2/13/20 2/14/20 2/15/20 2/16/20 2/17/20 2/ ⋯
     │ Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Float64 Fl ⋯
─────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1 │ 1.6596 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ⋯
                                                                                                                                                                                                                                                    394 columns omitted

```

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<div class="post-metadata">

**Author:** ![oo92](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oo92/32/22963_2.png) [@oo92](https://discourse.julialang.org/u/oo92)\
**Post date:** [March 19, 2021, 2:10am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/24 "2021-03-19T02:10:03Z")

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This is what I did:

```julia
begin
	algeria = df[df."Country/Region" .== "Algeria", 4:end]
	
	for i = 1:size(algeria, 2)
		if eltype(algeria[!, i]) .!= Float64
			algeria[!, i] = float.(algeria[!, i])
		end
	end
end

```

This is the error:

```julia
MethodError: no method matching AbstractFloat(::String)

Closest candidates are:

AbstractFloat(!Matched::Bool) at float.jl:258

AbstractFloat(!Matched::Int8) at float.jl:259

AbstractFloat(!Matched::Int16) at float.jl:260

...

float(::String)@float.jl:277
_broadcast_getindex_evalf@broadcast.jl:648[inlined]
_broadcast_getindex@broadcast.jl:621[inlined]
getindex@broadcast.jl:575[inlined]
macro expansion@broadcast.jl:932[inlined]
macro expansion@simdloop.jl:77[inlined]
copyto!@broadcast.jl:931[inlined]
copyto!@broadcast.jl:886[inlined]
copy@broadcast.jl:862[inlined]
materialize(::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1},Nothing,typeof(float),Tuple{Array{Union{Missing, String},1}}})@broadcast.jl:837
top-level scope@Local: 7

```

I am trying to get the columns for Algeria from the 4th column onwards…

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<div class="post-metadata">

**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [March 19, 2021, 2:12am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/25 "2021-03-19T02:12:58Z")

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> [@oo92](#):
>
> `algeria = df[df."Country/Region" .== "Algeria", 4:end]`

your algeria is already 4th column and forward of the original dataframe, I suspect you have some spelling error or something.

Can you try the whole snippet I pasted? Since they should do the same thing

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<div class="post-metadata">

**Author:** ![oo92](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oo92/32/22963_2.png) [@oo92](https://discourse.julialang.org/u/oo92)\
**Post date:** [March 19, 2021, 2:20am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/26 "2021-03-19T02:20:12Z")

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Yea it works in the terminal but does not work in Pluto. Let me send you my entire file:

```julia
begin
	using Pkg
	Pkg.add("PlutoUI")
	Pkg.add("Parquet")
	Pkg.add("StatsModels")
	Pkg.add("Missings")
	Pkg.add("Arrow")
	Pkg.activate(".")
	import CSV, DataFrames, Dates, StatsPlots, StatsModels, Statistics, Missings
	import DataFrames.DataFrame
	using Plots, PlutoUI, DelimitedFiles, Parquet, Arrow
end

begin
	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"))
end

begin
	dates = names(df)[5:end]
	countries = unique(df[:, :"Country/Region"])
end

begin
	algeria = df[df."Country/Region" .== "Algeria", 4:end]
	
	for i = 1:size(algeria, 2)
		if eltype(algeria[!, i]) .!= Float64
			algeria[!, i] = float.(algeria[!, i])
		end
	end
end

```

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<div class="post-metadata">

**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [March 19, 2021, 2:26am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/27 "2021-03-19T02:26:43Z")

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> [@oo92](#):
>
> ```julia
> 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"))
> 
> ```

please make up your mind as to what to use, this is not doing anything useful. Considering the data is so small, I’d just use csv+dataframe and forget about Arrow and Parquet.

I believe if you remove arrow and parquet this works, basically for the first begin block, only keep `df = CSV.read("temp.csv", DataFrame)`

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<div class="post-metadata">

**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [March 19, 2021, 2:29am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/28 "2021-03-19T02:29:30Z")

</div>

the root of your error is that, Parquet re-arranged your columns. so your country region states stuff are now at the end, thus when you do `4:end`, you are still including them.

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<div class="post-metadata">

**Author:** ![oo92](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oo92/32/22963_2.png) [@oo92](https://discourse.julialang.org/u/oo92)\
**Post date:** [March 19, 2021, 2:33am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/29 "2021-03-19T02:33:26Z")

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My friend, I have to do this chunk as part of an assignment. So this chunk of code has to exist whether I like it or not.

So if they’re at the end, do I do `begin:4`?

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<div class="post-metadata">

**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [March 19, 2021, 2:39am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/30 "2021-03-19T02:39:17Z")

</div>

well, it would be `begin:end-4`.

But in any case, if you need to do this dance, please inspect the final `df` that you’re actually doing operation on. (or better yet, don’t rely on the order of columns at all)

```julia
begin
    algeria = df[df."Country/Region" .== "Algeria", begin:end-4]
	
	for i = 1:size(algeria, 2)
		if eltype(algeria[!, i]) .!= Float64
			algeria[!, i] = float.(algeria[!, i])
		end
	end
end

```

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<div class="post-metadata">

**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [March 19, 2021, 6:54am UTC](https://discourse.julialang.org/t/how-to-parse-convert-integers-in-dataframe-to-float-numbers/57507/31 "2021-03-19T06:54:40Z")

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I would again **strongly** encourage you to work your way through [https://github.com/bkamins/Julia-DataFrames-Tutorial](https://github.com/bkamins/Julia-DataFrames-Tutorial)

While it might take you a day or two, understanding how things work and why they error will still save you loads of time compared to trying to debug a DataFrames analysis line by line on Discourse.

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