# Side effects (or intended effects) in TidierData?
**URL:** https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438
**Category:** Data
**Tags:** tidier
**Created:** [October 26, 2025, 2:26pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438 "2025-10-26T14:26:01Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [October 26, 2025, 2:26pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/1 "2025-10-26T14:26:01Z")
```julia-auto
julia> df4 = DataFrame(x = ["a", "b", "a", "b", "C", "a"], y = 1:6, yz = 13:18, a = [join(rand('a':'z',4)) for _ in 1:6], ab = 12:-1:7)
6×5 DataFrame
Row │ x y yz a ab
│ String Int64 Int64 String Int64
─────┼─────────────────────────────────────
1 │ a 1 13 coes 12
2 │ b 2 14 nwoz 11
3 │ a 3 15 gber 10
4 │ b 4 16 ompu 9
5 │ C 5 17 ktgq 8
6 │ a 6 18 edkt 7
julia> nested_df = @nest(df4, n2 = starts_with("a"), n3 = y:yz)
3×3 DataFrame
Row │ x n3 n2
│ String DataFrame DataFrame
─────┼──────────────────────────────────────
1 │ a 3×2 DataFrame 3×2 DataFrame
2 │ b 2×2 DataFrame 2×2 DataFrame
3 │ C 1×2 DataFrame 1×2 DataFrame
julia> @chain nested_df begin
@unnest_wider(n3:n2, names_sep = nothing)
@unnest_longer(y:ab)
end
9×5 DataFrame
Row │ x y yz a ab
│ String Int64? Int64? Any Int64?
─────┼─────────────────────────────────────────
1 │ a 1 13 coes 12
2 │ a 3 15 gber 10
3 │ a 6 18 edkt 7
4 │ b 2 14 nwoz 11
5 │ b 4 16 ompu 9
6 │ C 5 17 k 8
7 │ C missing missing t missing
8 │ C missing missing g missing
9 │ C missing missing q missing
```
---
### Author:  [@eteppo](https://discourse.julialang.org/u/eteppo)
#### Post date: [October 27, 2025, 2:07pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/2 "2025-10-27T14:07:43Z")
That looks unfortunate, probably want to open an issue? If you use CategoricalArrays or symbols or something, you get an error that there is no iterate-method for it. The String is happy with it.
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [October 27, 2025, 3:31pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/3 "2025-10-27T15:31:29Z")
I don’t know how to open an issue. I just wanted to point out something that apparently (but I may be wrong) isn’t consistent with the rest of the examples in the manual chapter on @unnest\_xyz macros.
If you also think it is a relevant fact, please make the issue yourself.
---
### Author:  [@ufechner7](https://discourse.julialang.org/u/ufechner7)
#### Post date: [October 27, 2025, 3:56pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/4 "2025-10-27T15:56:33Z")
> [@rocco\_sprmnt21](#):
>
> I don’t know how to open an issue.
That is really not difficult and worth to learn. Just go to [GitHub · Where software is built](https://github.com/TidierOrg/TidierData.jl/issues) and click on the button “New Issue”.
Then describe the issue you encountered, preferably including an example.
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [October 28, 2025, 10:17pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/5 "2025-10-28T22:17:52Z")
[is that okay?](https://github.com/TidierOrg/TidierData.jl/issues/160)
---
### Author:  [@ufechner7](https://discourse.julialang.org/u/ufechner7)
#### Post date: [October 28, 2025, 10:23pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/6 "2025-10-28T22:23:26Z")
Not really. An issue should contain:
- the code you executed
- the output of executing that code
- the expected output
and usually also the output of the command:
```julia-auto
versioninfo()
```
Sometimes a link to discourse can be useful, but an issue should not only contain the link to a discussion on discourse.
---
### Author:  [@drizk1](https://discourse.julialang.org/u/drizk1)
#### Post date: [October 28, 2025, 11:39pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/7 "2025-10-28T23:39:54Z")
> [@rocco\_sprmnt21](#):
>
> ```julia-auto
> @chain nested_df begin
> @unnest_wider(n3:n2, names_sep = nothing)
> @unnest_longer(y:ab)
> end
>
> ```
thank you for pointing this out. this is not intended.
it seemed to be an issue when unnesting wider before longer… which was not intended.
I have now fixed it in the “unnest\_wider\_edgecase” branch.
```julia-auto
julia> nested_df = @nest(df4, n2 = starts_with("a"), n3 = y:yz)
3×3 DataFrame
Row │ x n3 n2
│ String DataFrame DataFrame
─────┼──────────────────────────────────────
1 │ a 3×2 DataFrame 3×2 DataFrame
2 │ b 2×2 DataFrame 2×2 DataFrame
3 │ C 1×2 DataFrame 1×2 DataFrame
julia> @chain nested_df begin
@unnest_wider(n3:n2, names_sep = nothing)
@unnest_longer(y:ab)
end
6×5 DataFrame
Row │ x y yz a ab
│ String Int64 Int64 String Int64
─────┼─────────────────────────────────────
1 │ a 1 13 yzyb 12
2 │ a 3 15 tijm 10
3 │ a 6 18 dxcd 7
4 │ b 2 14 ijkj 11
5 │ b 4 16 gavn 9
6 │ C 5 17 zvtt 8
julia> @chain nested_df begin
@unnest_longer(n3:n2)
@unnest_wider(n3:n2, names_sep = nothing)
end
6×5 DataFrame
Row │ x yz y a ab
│ String Int64 Int64 String Int64
─────┼─────────────────────────────────────
1 │ a 13 1 yzyb 12
2 │ a 15 3 tijm 10
3 │ a 18 6 dxcd 7
4 │ b 14 2 ijkj 11
5 │ b 16 4 gavn 9
6 │ C 17 5 zvtt 8
```
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [October 29, 2025, 10:21pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/8 "2025-10-29T22:21:04Z")
Is it possible to update to the fixed version?
How?
---
### Author:  [@drizk1](https://discourse.julialang.org/u/drizk1)
#### Post date: [October 30, 2025, 1:44am UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/9 "2025-10-30T01:44:15Z")
You can add the specific branch by doing
```julia-auto
(@v1.11) pkg> add TidierData#unnest_wider_edgecase
```
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [October 30, 2025, 6:01pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/10 "2025-10-30T18:01:28Z")
I updated following the instructions
I don’t want to overwhelm your attention (I also confess that none of the following cases are of practical interest to me, but it’s just pure curiosity), and if you don’t find it useful to dwell on these observations, I’d understand.
Now suppose we have the following DataFrame.
The results of the following flattenings are clear to me for the first case but not for the last two.
```julia-auto
julia> df4
6×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 Any String Any
─────┼──────────────────────────────────────────────────────
1 │ a 1 13 ["AAA", "BBB"] ttyu 12
2 │ b 2 14 quk ojx 11
3 │ a 3 15 sfgdb ufo 10
4 │ b 4 16 upku pgafaq 9
5 │ C 5 17 dhmvk yggc 8
6 │ a 6 18 hfz zpfun [7, 7]
julia> @unnest_longer( df4,[ab])
7×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 Any String Int64
─────┼─────────────────────────────────────────────────────
1 │ a 1 13 ["AAA", "BBB"] ttyu 12
2 │ b 2 14 quk ojx 11
3 │ a 3 15 sfgdb ufo 10
4 │ b 4 16 upku pgafaq 9
5 │ C 5 17 dhmvk yggc 8
6 │ a 6 18 hfz zpfun 7
7 │ a 6 18 hfz zpfun 7
julia> @unnest_longer( df4,a)
22×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 Any String Any
─────┼───────────────────────────────────────────
1 │ a 1 13 AAA ttyu 12
2 │ a 1 13 BBB ttyu 12
3 │ b 2 14 q ojx 11
4 │ b 2 14 u ojx 11
5 │ b 2 14 k ojx 11
6 │ a 3 15 s ufo 10
7 │ a 3 15 f ufo 10
8 │ a 3 15 g ufo 10
9 │ a 3 15 d ufo 10
10 │ a 3 15 b ufo 10
11 │ b 4 16 u pgafaq 9
12 │ b 4 16 p pgafaq 9
13 │ b 4 16 k pgafaq 9
14 │ b 4 16 u pgafaq 9
15 │ C 5 17 d yggc 8
16 │ C 5 17 h yggc 8
17 │ C 5 17 m yggc 8
18 │ C 5 17 v yggc 8
19 │ C 5 17 k yggc 8
20 │ a 6 18 h zpfun [7, 7]
21 │ a 6 18 f zpfun [7, 7]
22 │ a 6 18 z zpfun [7, 7]
julia> @unnest_longer( df4,a,ab)
22×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 Any String Int64?
─────┼────────────────────────────────────────────
1 │ a 1 13 AAA ttyu 12
2 │ a 1 13 BBB ttyu missing
3 │ b 2 14 q ojx 11
4 │ b 2 14 u ojx missing
5 │ b 2 14 k ojx missing
6 │ a 3 15 s ufo 10
7 │ a 3 15 f ufo missing
8 │ a 3 15 g ufo missing
9 │ a 3 15 d ufo missing
10 │ a 3 15 b ufo missing
11 │ b 4 16 u pgafaq 9
12 │ b 4 16 p pgafaq missing
13 │ b 4 16 k pgafaq missing
14 │ b 4 16 u pgafaq missing
15 │ C 5 17 d yggc 8
16 │ C 5 17 h yggc missing
17 │ C 5 17 m yggc missing
18 │ C 5 17 v yggc missing
19 │ C 5 17 k yggc missing
20 │ a 6 18 h zpfun 7
21 │ a 6 18 f zpfun 7
22 │ a 6 18 z zpfun missing
```
---
### Author:  [@drizk1](https://discourse.julialang.org/u/drizk1)
#### Post date: [October 31, 2025, 4:50am UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/11 "2025-10-31T04:50:31Z")
> [@drizk1](#):
>
> ```julia-auto
> @chain nested_df begin
> @unnest_longer(n3:n2)
> @unnest_wider(n3:n2, names_sep = nothing)
> end
>
> ```
this was an edge case that slipped by me in testing actually. thank you for pointing it out. It is now fixed in that same branch if you re download it. I have compared it to the R implementation as well to confirm they match
```julia-auto
julia> df4 = DataFrame(
x = ["a", "b", "a", "b", "C", "a"],
y = [1, 2, 3, 4, 5, 6],
yz = [13, 14, 15, 16, 17, 18],
a = [["AAA", "BBB"], "quk", "sfgdb", "upku", "dhmvk", "hfz" ],
b = ["ttyu", "ojx", "ufo", "pgafaq", "yggc", "zpfun"],
ab = [12, 11, 10, 9, 8, [7, 7]]
);
julia> @unnest_longer( df4,a)
7×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 String String Any
─────┼──────────────────────────────────────────────
1 │ a 1 13 AAA ttyu 12
2 │ a 1 13 BBB ttyu 12
3 │ b 2 14 quk ojx 11
4 │ a 3 15 sfgdb ufo 10
5 │ b 4 16 upku pgafaq 9
6 │ C 5 17 dhmvk yggc 8
7 │ a 6 18 hfz zpfun [7, 7]
julia> @unnest_longer(df4, a, ab)
8×6 DataFrame
Row │ x y yz a b ab
│ String Int64 Int64 String String Int64
─────┼─────────────────────────────────────────────
1 │ a 1 13 AAA ttyu 12
2 │ a 1 13 BBB ttyu 12
3 │ b 2 14 quk ojx 11
4 │ a 3 15 sfgdb ufo 10
5 │ b 4 16 upku pgafaq 9
6 │ C 5 17 dhmvk yggc 8
7 │ a 6 18 hfz zpfun 7
8 │ a 6 18 hfz zpfun 7
```
---
### Author:  [@digital\_carver](https://discourse.julialang.org/u/digital_carver)
#### Post date: [October 31, 2025, 10:53pm UTC](https://discourse.julialang.org/t/side-effects-or-intended-effects-in-tidierdata/133438/12 "2025-10-31T22:53:35Z")
> [@drizk1](#):
>
> It is not fixed in that same branch if you re download it.
This is a typo maybe? Based on [this commit](https://github.com/TidierOrg/TidierData.jl/pull/156/commits/8f78b4017db5b40eb206985f557b4ef54284716b), perhaps you meant to say “It is _now_ fixed” there?