# \#dataframes

**URL:** https://discourse.julialang.org/tag/dataframes/192.md

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## [Combine(groupby())](https://discourse.julialang.org/t/combine-groupby/139142)

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**Author:** [@mahmah](https://discourse.julialang.org/u/mahmah)\
**Replies:** 8\
**Last updated:** [September 2, 2026, 2:32pm UTC](https://discourse.julialang.org/t/combine-groupby/139142 "2026-09-02T14:32:35Z")

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Is there a way to do this: c = combine(groupby(df, :A),:B =\> mean =\> :B\_mean) but in such a way that the output does not only show :A and :B\_mean but also the other variables that df had (well, at least the variables t…

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## [Reading large CSV files](https://discourse.julialang.org/t/reading-large-csv-files/139061)

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**Author:** [@mahmah](https://discourse.julialang.org/u/mahmah)\
**Replies:** 9\
**Last updated:** [August 31, 2026, 11:56am UTC](https://discourse.julialang.org/t/reading-large-csv-files/139061 "2026-08-31T11:56:40Z")

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Hi, is there any way to read a 88 GB csv file into a DataFrame? It kills julia, even with the -t auto option. Thanks!

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## [Generate excel spreadsheet from julia equations?](https://discourse.julialang.org/t/generate-excel-spreadsheet-from-julia-equations/92444)

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**Author:** [@OliverEvans96](https://discourse.julialang.org/u/OliverEvans96)\
**Replies:** 1\
**Last updated:** [August 29, 2026, 5:43pm UTC](https://discourse.julialang.org/t/generate-excel-spreadsheet-from-julia-equations/92444 "2026-08-29T17:43:11Z")

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Hi all, Imagine a spreadsheet with columns A, B, C. Suppose A are observations, and B = B(A), C = C(A, B) are defined by excel formulas involving the previous columns. This is a pretty common scenario in excel. I was j…

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## [Sending excel file as response is slow](https://discourse.julialang.org/t/sending-excel-file-as-response-is-slow/116705)

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**Author:** [@Sandy45](https://discourse.julialang.org/u/Sandy45)\
**Replies:** 8\
**Last updated:** [August 29, 2026, 4:46pm UTC](https://discourse.julialang.org/t/sending-excel-file-as-response-is-slow/116705 "2026-08-29T16:46:40Z")

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I have an API which get csv file in the request and all I need to do is format and send the response as excel file. I am reading the data into dataframe and directly writing into excel. The issue is that writing data in…

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## [Reading compressed csv gzopen cuts file short](https://discourse.julialang.org/t/reading-compressed-csv-gzopen-cuts-file-short/137885)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 4\
**Last updated:** [July 1, 2026, 5:31pm UTC](https://discourse.julialang.org/t/reading-compressed-csv-gzopen-cuts-file-short/137885 "2026-07-01T17:31:48Z")

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I seem to have stumbled into some kind of bug. I am working with large compressed CSV files. I’m loading the data with: mydata = gzopen(x-\>CSV.read(x, DataFrame), mydatafile) Then I just get this warning: ┌ Warning: t…

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## [Dataframe data manipulation](https://discourse.julialang.org/t/dataframe-data-manipulation/136950)

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**Author:** [@SergeantMike67](https://discourse.julialang.org/u/SergeantMike67)\
**Replies:** 7\
**Last updated:** [June 4, 2026, 3:48pm UTC](https://discourse.julialang.org/t/dataframe-data-manipulation/136950 "2026-06-04T15:48:45Z")

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I have a data frame that is formatted like the example below. Row │ Pairwise p\_adj boo Factor IntBoo │ String Float64 Bool String …

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## [Short Documentary Video: An Experimental Emotional AI Model Running as an HTTP API (in Julia)](https://discourse.julialang.org/t/short-documentary-video-an-experimental-emotional-ai-model-running-as-an-http-api-in-julia/136934)

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**Author:** [@mouad-tarif](https://discourse.julialang.org/u/mouad-tarif)\
**Replies:** 0\
**Last updated:** [April 30, 2026, 4:57pm UTC](https://discourse.julialang.org/t/short-documentary-video-an-experimental-emotional-ai-model-running-as-an-http-api-in-julia/136934 "2026-04-30T16:57:34Z")

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I published a video showing an experimental model that interacts with basic emotions and is accessible via an API. What appears in the video: An HTTP server (using HTTP.jl) handling requests. The model responding to e…

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## [My journey training an LLM from scratch in Julia (and why I see huge potential)](https://discourse.julialang.org/t/my-journey-training-an-llm-from-scratch-in-julia-and-why-i-see-huge-potential/136843)

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**Author:** [@mouad-tarif](https://discourse.julialang.org/u/mouad-tarif)\
**Replies:** 5\
**Last updated:** [April 24, 2026, 5:07pm UTC](https://discourse.julialang.org/t/my-journey-training-an-llm-from-scratch-in-julia-and-why-i-see-huge-potential/136843 "2026-04-24T17:07:59Z")

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I started training a language model from scratch in Julia. Not using pre-built libraries for the core - building my own BPE tokenizer, my own training loop, facing hallucinations, and rebuilding. I tried Flux and Lux. B…

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## [AtlanticCloud.jl — typed Julia access to the Atlantic Cloud geospatial data infrastructure](https://discourse.julialang.org/t/atlanticcloud-jl-typed-julia-access-to-the-atlantic-cloud-geospatial-data-infrastructure/136655)

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**Author:** [@joao-pinelo](https://discourse.julialang.org/u/joao-pinelo)\
**Replies:** 0\
**Last updated:** [April 9, 2026, 4:29pm UTC](https://discourse.julialang.org/t/atlanticcloud-jl-typed-julia-access-to-the-atlantic-cloud-geospatial-data-infrastructure/136655 "2026-04-09T16:29:08Z")

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AtlanticCloud.jl — typed Julia access to the Atlantic Cloud geospatial data infrastructure We’ve just released AtlanticCloud.jl v0.3.0 — a client for the Atlantic Cloud, a transatlantic computation and data network opera…

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## [Perplexed by behavior of module scope changing variables](https://discourse.julialang.org/t/perplexed-by-behavior-of-module-scope-changing-variables/136075)

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**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 2\
**Last updated:** [March 7, 2026, 1:06am UTC](https://discourse.julialang.org/t/perplexed-by-behavior-of-module-scope-changing-variables/136075 "2026-03-07T01:06:08Z")

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Hello, I must be doing something wrong. Can someone explain this behavior to me? module A using DataFrames x = DataFrame(a=\[1,3\],b=\[4,3\]) export x end module B using ..A function add\_stuff(df…

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## [How to convert long form data frame for contour plot](https://discourse.julialang.org/t/how-to-convert-long-form-data-frame-for-contour-plot/135937)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 2\
**Last updated:** [March 1, 2026, 2:25pm UTC](https://discourse.julialang.org/t/how-to-convert-long-form-data-frame-for-contour-plot/135937 "2026-03-01T14:25:58Z")

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Hello, As shown in the MWE below, I have a data frame with three variables in long form and would like to plot it as a contour plot. There are two issues. First, the variables x and y span a triangular area rather than …

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## [How to create a DataFrame from code literals, especially with Unitful?](https://discourse.julialang.org/t/how-to-create-a-dataframe-from-code-literals-especially-with-unitful/135613)

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**Author:** [@bertulli](https://discourse.julialang.org/u/bertulli)\
**Replies:** 8\
**Last updated:** [February 13, 2026, 6:35pm UTC](https://discourse.julialang.org/t/how-to-create-a-dataframe-from-code-literals-especially-with-unitful/135613 "2026-02-13T18:35:45Z")

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Hi all! I’m working with some physical quantities and I’d like to use Unitful.jl for that. I am wondering two things: what is the most easily maintainable, and/or efficient way to crate a DataFrame from code literals (…

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## [Pre-computing Groupings for DataFrames?](https://discourse.julialang.org/t/pre-computing-groupings-for-dataframes/134973)

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**Author:** [@nateybear](https://discourse.julialang.org/u/nateybear)\
**Replies:** 6\
**Last updated:** [January 10, 2026, 9:12pm UTC](https://discourse.julialang.org/t/pre-computing-groupings-for-dataframes/134973 "2026-01-10T21:12:05Z")

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Hi! I’m writing to check my understanding of a computational problem and see if I am approaching things correctly. I am writing estimation code that needs to traverse data in multiple different ways. The typical approac…

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## [Is there a way to easily typecast a DataFrame](https://discourse.julialang.org/t/is-there-a-way-to-easily-typecast-a-dataframe/134919)

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**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 8\
**Last updated:** [January 7, 2026, 9:22pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-easily-typecast-a-dataframe/134919 "2026-01-07T21:22:37Z")

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Hello, Is there a way to easily auto typecast a DataFrame? For context, I’m doing some data wrangling with dirty data and each column has the type “Any” as the values in a column might be an int, string, missing, etc. …

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## [Plot every columns of a DataFrame](https://discourse.julialang.org/t/plot-every-columns-of-a-dataframe/134808)

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**Author:** [@Ju\_ska](https://discourse.julialang.org/u/Ju_ska)\
**Replies:** 5\
**Last updated:** [January 7, 2026, 6:58pm UTC](https://discourse.julialang.org/t/plot-every-columns-of-a-dataframe/134808 "2026-01-07T18:58:41Z")

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Hi, I would like to stack plots on top of each other without having to manage columns. Like separating the x axis from every other columns, then plot. using DataFrames using Plots df = DataFrame(x = \[1,2,3,4\], y1 = \[…

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## [@chaineach](https://discourse.julialang.org/t/chaineach/134423)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 12\
**Last updated:** [December 9, 2025, 12:10am UTC](https://discourse.julialang.org/t/chaineach/134423 "2025-12-09T00:10:13Z")

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I’d like a macro @chaineach such that: @chaineach x begin #commands end is equivalent to map( y -\> @chain y begin #commands end, collect(x) ) Example usage is a @chain block processing a DataFrame and creati…

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## [Alternative to map() for grouped dataframe?](https://discourse.julialang.org/t/alternative-to-map-for-grouped-dataframe/134038)

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**Author:** [@Quantodeluz](https://discourse.julialang.org/u/Quantodeluz)\
**Replies:** 9\
**Last updated:** [November 22, 2025, 9:42pm UTC](https://discourse.julialang.org/t/alternative-to-map-for-grouped-dataframe/134038 "2025-11-22T21:42:04Z")

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I’m trying to do one quadratic fit per subdataframe on a grouped dataframe (using two of it’s columns obviously), but i can’t use map() to do it because it’s reserved, and doing a list comprehension throws an error becau…

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## [\`MethodError\` when trying to \`filter\` a \`GroupedDataframe\`](https://discourse.julialang.org/t/methoderror-when-trying-to-filter-a-groupeddataframe/133996)

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**Author:** [@Quantodeluz](https://discourse.julialang.org/u/Quantodeluz)\
**Replies:** 5\
**Last updated:** [November 20, 2025, 2:52am UTC](https://discourse.julialang.org/t/methoderror-when-trying-to-filter-a-groupeddataframe/133996 "2025-11-20T02:52:24Z")

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I’m trying to filter the SubDataFrames with less than a given length (nrow) out of a GroupedDataFrame, but filter() doesn’t seem to recognize the anonymus function i’m passing to it and throws a MethodError: ERROR: Load…

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## [Save a DataFrame preserving a column of matrices](https://discourse.julialang.org/t/save-a-dataframe-preserving-a-column-of-matrices/133895)

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**Author:** [@contradict](https://discourse.julialang.org/u/contradict)\
**Replies:** 4\
**Last updated:** [November 17, 2025, 4:59pm UTC](https://discourse.julialang.org/t/save-a-dataframe-preserving-a-column-of-matrices/133895 "2025-11-17T16:59:02Z")

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I have a DataFrame with a column of 3x3 Float32 matrices. I would like to save this to a file and later read it back, preserving this column. I tried this round trip with several tools: CSV =\> converts to String JSONTab…

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## [With DataFrames, best practice for applying function across columns, where we also need to reference, in a second argument, the same column for each function call?](https://discourse.julialang.org/t/with-dataframes-best-practice-for-applying-function-across-columns-where-we-also-need-to-reference-in-a-second-argument-the-same-column-for-each-function-call/127747)

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**Author:** [@midnightgreen](https://discourse.julialang.org/u/midnightgreen)\
**Replies:** 12\
**Last updated:** [November 11, 2025, 11:28pm UTC](https://discourse.julialang.org/t/with-dataframes-best-practice-for-applying-function-across-columns-where-we-also-need-to-reference-in-a-second-argument-the-same-column-for-each-function-call/127747 "2025-11-11T23:28:01Z")

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This is somewhat difficult to put into words, however, I have two examples of this type of operation and I am unsure how best to tackle it in Julia. Take a weighted sum of a column within a grouping variable; repeat th…

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## [Plot gets jumbled up when a map is applied](https://discourse.julialang.org/t/plot-gets-jumbled-up-when-a-map-is-applied/132995)

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**Author:** [@Quantodeluz](https://discourse.julialang.org/u/Quantodeluz)\
**Replies:** 2\
**Last updated:** [October 9, 2025, 8:48pm UTC](https://discourse.julialang.org/t/plot-gets-jumbled-up-when-a-map-is-applied/132995 "2025-10-09T20:48:11Z")

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I have some temperature decay data, and i’m trying to graph \\frac{T-T\_a}{T\_0-T\_a} vs t. So i applied a simple mapping: map(T-\>(T-Ta)/(df.temp\_cº\[1\]-Ta), df.temp\_cº), and it gave me this (with two different datasets): …

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## [Dataframe columns type is \`Any\` even though it's initialized with all \`Float64\`](https://discourse.julialang.org/t/dataframe-columns-type-is-any-even-though-its-initialized-with-all-float64/132870)

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**Author:** [@Quantodeluz](https://discourse.julialang.org/u/Quantodeluz)\
**Replies:** 3\
**Last updated:** [October 4, 2025, 7:08am UTC](https://discourse.julialang.org/t/dataframe-columns-type-is-any-even-though-its-initialized-with-all-float64/132870 "2025-10-04T07:08:06Z")

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I don’t have much more to add, I even rerun the code but initializing the columns with the type as a string, and still: The two columns before them are fine, but no matter what i do these have type Any, and that’s ma…

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## [How to text-save a DataFrame in markdown?](https://discourse.julialang.org/t/how-to-text-save-a-dataframe-in-markdown/132628)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 12\
**Last updated:** [October 3, 2025, 1:26pm UTC](https://discourse.julialang.org/t/how-to-text-save-a-dataframe-in-markdown/132628 "2025-10-03T13:26:20Z")

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I know about PrettyTables, but how do I save to file, let’s say table\_xy.md, a DataFrame ?

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## [How to hide the types line when pretty printing a data frame](https://discourse.julialang.org/t/how-to-hide-the-types-line-when-pretty-printing-a-data-frame/33393)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 9\
**Last updated:** [October 3, 2025, 11:25am UTC](https://discourse.julialang.org/t/how-to-hide-the-types-line-when-pretty-printing-a-data-frame/33393 "2025-10-03T11:25:31Z")

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I’m sure this was mentioned before, I just can’t find it in PrettyTables.jl’s documentation nor here on Discourse. How can I hide the row indicating the columns’ types when printing a DataFrame? julia\> using DataFrames,…

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## [Dataframe viewer needed](https://discourse.julialang.org/t/dataframe-viewer-needed/9239)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 28\
**Last updated:** [September 23, 2025, 12:36pm UTC](https://discourse.julialang.org/t/dataframe-viewer-needed/9239 "2025-09-23T12:36:25Z")

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I think a dataframe viewer where I can look at each row and column and if needed can scroll across up and down are needed. I know atom has a CSV editor plugin. Perhaps can repurpose that. I know it’s a lot of work but i…

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## [Packages for representing time series data](https://discourse.julialang.org/t/packages-for-representing-time-series-data/84699)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 14\
**Last updated:** [September 23, 2025, 12:55pm UTC](https://discourse.julialang.org/t/packages-for-representing-time-series-data/84699 "2025-09-23T12:55:50Z")

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DataFrames.jl seems to be the go to package for representing tabular data. It is very performant and well maintained. However, if someone has strictly structured data like time series data (i.e. a vector of timestamp an…

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## [Change struct dataframe value correct way](https://discourse.julialang.org/t/change-struct-dataframe-value-correct-way/132121)

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**Author:** [@rdl987](https://discourse.julialang.org/u/rdl987)\
**Replies:** 6\
**Last updated:** [September 8, 2025, 3:02pm UTC](https://discourse.julialang.org/t/change-struct-dataframe-value-correct-way/132121 "2025-09-08T15:02:05Z")

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Hello I have a struct with inside other two structs: Base.@kwdef mutable struct MyDataset input::MyInputDataset = MyInputDataset() processed::MyInputDataset = MyInputDataset() end Base.@kwdef mutable struct MyInput…

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## [Help setting a filter that can return missing or non-missing values](https://discourse.julialang.org/t/help-setting-a-filter-that-can-return-missing-or-non-missing-values/132181)

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**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 4\
**Last updated:** [September 8, 2025, 2:44pm UTC](https://discourse.julialang.org/t/help-setting-a-filter-that-can-return-missing-or-non-missing-values/132181 "2025-09-08T14:44:27Z")

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Hi all, Is there no way to specifically filter for missing values in a DataFrame column that is compatible with filtering for non-missing values (e.g. so a single filter can loop through non-missing and missing?) Take …

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## [Convert a PythonCall df to Julia df, incomplete conversion](https://discourse.julialang.org/t/convert-a-pythoncall-df-to-julia-df-incomplete-conversion/132054)

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**Author:** [@Ju\_ska](https://discourse.julialang.org/u/Ju_ska)\
**Replies:** 6\
**Last updated:** [September 3, 2025, 6:02am UTC](https://discourse.julialang.org/t/convert-a-pythoncall-df-to-julia-df-incomplete-conversion/132054 "2025-09-03T06:02:34Z")

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Hi, I have a PythonCall result looking like: julia\> forecast Python: ds trend yhat\_lower ... multiplicative\_terms\_lower multiplicative\_terms\_upper yhat 0 2024-04-08 06:19…

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## [Adding rows to data frame](https://discourse.julialang.org/t/adding-rows-to-data-frame/131925)

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**Author:** [@SergeantMike](https://discourse.julialang.org/u/SergeantMike)\
**Replies:** 2\
**Last updated:** [August 29, 2025, 1:37am UTC](https://discourse.julialang.org/t/adding-rows-to-data-frame/131925 "2025-08-29T01:37:47Z")

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I have a dataset that looks like this: Elapsed Days Insects Collected on that day 1 0 2 3 4 25 5 21 6 14 8 2 and I have a second dataset that is similar but is missing different days Elapsed Da…

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