# Strange DataFrame results
**URL:** https://discourse.julialang.org/t/strange-dataframe-results/36351
**Category:** General Usage
**Created:** [March 22, 2020, 5:02pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351 "2020-03-22T17:02:57Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@jonjilla](https://discourse.julialang.org/u/jonjilla)
#### Post date: [March 22, 2020, 5:02pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/1 "2020-03-22T17:02:57Z")
Hello
I have a strange issue. I have many places where I’m first creating an array of Dictionaries and then converting it to a DataFrame at the end. This works fine and is fast enough for my purposes. In most cases, it works perfectly well, but recently, I found one case where the dataFrame contents weren’t what I was expecting.
Instead of the names of the DataFrame being the keys of the dictionaries, they were always generated like the following
```julia
names(df)
8-element Array{Symbol,1}:
:slots
:keys
:vals
:ndel
:count
:age
:idxfloor
:maxprobe
```
If I take any one of elements of the Array of Dictionaries and convert it as a single Dictionary into a DataFrame it works OK (I looped through every row and each row by itself comes out OK) but only when I take the entire Array at once, does this occur, but as I noted, I do this in many other places without issue.
I suspect that this is some sort of internal dataframe representation, but I can’t figure out why in this one case, it is being generated like this? Does someone know what this means and what condition could possibly create it?
---
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [March 22, 2020, 5:08pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/2 "2020-03-22T17:08:35Z")
This is strange. Can you make an MWE? It’s hard to tell exactly what is going on without one.
Things are working fine for me.
```julia
julia> d = [Dict(:a => 5, :b => 7), Dict(:a => 100, :b => 89)]
2-element Array{Dict{Symbol,Int64},1}:
Dict(:a => 5,:b => 7)
Dict(:a => 100,:b => 89)
julia> DataFrame(d)
2×2 DataFrame
│ Row │ a │ b │
│ │ Int64 │ Int64 │
├─────┼───────┼───────┤
│ 1 │ 5 │ 7 │
│ 2 │ 100 │ 89 │
```
---
### Author:  [@jonjilla](https://discourse.julialang.org/u/jonjilla)
#### Post date: [March 23, 2020, 2:25pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/3 "2020-03-23T14:25:30Z")
I’ve tested various configurations and found that this simple case replicates the issue
```julia
test = Array(Dict[])
push!(test, Dict("test" => "1"))
push!(test, Dict("test" => "2"))
DataFrame(test)
│ Row │ slots │ keys │
│ │ Array{UInt8,1} │ Array{String,1} │
├─────┼──────────────────────────────────────────────────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ 1 │ [0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] │ [#undef, #undef, #undef, #undef, "test", #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef] │
│ 2 │ [0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] │ [#undef, #undef, #undef, #undef, "test", #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef, #undef] │
```
if I switch the keys to Symbols, then it works OK
```julia
test = Array(Dict[])
push!(test, Dict(:test => "1"))
push!(test, Dict(:test => "2"))
julia> DataFrame(test)
2×1 DataFrame
│ Row │ test │
│ │ String │
├─────┼────────┤
│ 1 │ 1 │
│ 2 │ 2 │
```
Is this expected that we cannot use string keys?
---
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [March 23, 2020, 2:36pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/4 "2020-03-23T14:36:25Z")
The behavior is certainly bizarre and we should throw an error instead of have this behavior.
But ultimately, yes. You should use `Symbols`.
---
### Author:  [@jonjilla](https://discourse.julialang.org/u/jonjilla)
#### Post date: [March 23, 2020, 7:45pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/5 "2020-03-23T19:45:55Z")
but it looks like it works OK, if I use a single dictionary with string keys
Is this really not allowed?
```julia
julia> d = Dict("test" => "1")
Dict{String,String} with 1 entry:
"test" => "1"
julia> DataFrame(d)
1×1 DataFrame
│ Row │ test │
│ │ String │
├─────┼────────┤
│ 1 │ 1 │
```
---
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [March 23, 2020, 7:59pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/6 "2020-03-23T19:59:47Z")
DataFrames don’t use `Strings` as column names, they use `Symbols`. So you shouldn’t expect using a `String` to work.
It’s pretty easy to turn a `String` into a `Symbol`, via `Symbol(s)`.
---
### Author:  [@bkamins](https://discourse.julialang.org/u/bkamins)
#### Post date: [March 23, 2020, 8:01pm UTC](https://discourse.julialang.org/t/strange-dataframe-results/36351/7 "2020-03-23T20:01:55Z")
The problem (or a feature) is not with DataFrames.jl but with Tables.jl (and DataFrames.jl falls back to Times.jl) and Tables.jl defines the following rules:
```julia
julia> d = Dict(:test => "1")
Dict{Symbol,String} with 1 entry:
:test => "1"
julia> Tables.isrowtable([d, d])
true
julia> d = Dict("test" => "1")
Dict{String,String} with 1 entry:
"test" => "1"
julia> Tables.isrowtable([d, d])
false
```