# Data

**URL:** https://discourse.julialang.org/c/domain/data/16.md?page=35

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**Page:** 36

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## [ANN: uCSV.jl](https://discourse.julialang.org/t/ann-ucsv-jl/6162)

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**Author:** [@cjprybol](https://discourse.julialang.org/u/cjprybol)\
**Replies:** 4\
**Last updated:** [October 3, 2017, 8:04am UTC](https://discourse.julialang.org/t/ann-ucsv-jl/6162 "2017-10-03T08:04:40Z")

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uCSV.jl is a µ-sized package for working with delimited text. The default behavior is similar to readcsv from base, but it is extensible enough to cover just about everything you’d expect from more established parsers in…

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## [Issues with multiple @let statements in Query.jl](https://discourse.julialang.org/t/issues-with-multiple-let-statements-in-query-jl/4494)

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**Author:** [@Matt\_Amos](https://discourse.julialang.org/u/Matt_Amos)\
**Replies:** 5\
**Last updated:** [September 29, 2017, 5:38am UTC](https://discourse.julialang.org/t/issues-with-multiple-let-statements-in-query-jl/4494 "2017-09-29T05:38:19Z")

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Whenever I try to use more than two @let statements in my query I get an error (Julia version 0.6.0, Query.jl 0.6.0). DataFrame sink: type TypeofBottom has no field parameters Array sink: TypeError: getfield: expecte…

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## [Problem Installing RDatasets and DataFrames](https://discourse.julialang.org/t/problem-installing-rdatasets-and-dataframes/6121)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 5\
**Last updated:** [September 28, 2017, 7:48am UTC](https://discourse.julialang.org/t/problem-installing-rdatasets-and-dataframes/6121 "2017-09-28T07:48:30Z")

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Can someone help me make sure my julia installation is correct? There are a few things that seem sketchy when I try to install and update the DataFrames package and the RDatasets Package First, when I issue the command …

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## [DataFrames: why is \`df\[2,\]\` the same as \`df\[2\]\`?](https://discourse.julialang.org/t/dataframes-why-is-df-2-the-same-as-df-2/6053)

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**Author:** [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Replies:** 17\
**Last updated:** [September 27, 2017, 9:33pm UTC](https://discourse.julialang.org/t/dataframes-why-is-df-2-the-same-as-df-2/6053 "2017-09-27T21:33:53Z")

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Curious about the rationale for this. Seems like df\[2,\] should either be the second row (same as df\[2,:\]) or an error. Thanks

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## [Help needed with DataFrames and Query](https://discourse.julialang.org/t/help-needed-with-dataframes-and-query/6077)

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**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 8\
**Last updated:** [September 27, 2017, 1:01pm UTC](https://discourse.julialang.org/t/help-needed-with-dataframes-and-query/6077 "2017-09-27T13:01:26Z")

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I am learning how to use DataFrames and find am struggling to use it for what I need it for. My present problem is illustrated by this attempt to use Quey.jl. I cannot understand why there result of q1 has no values. A…

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## [Adding Excel File to Jupyter Notebook](https://discourse.julialang.org/t/adding-excel-file-to-jupyter-notebook/6098)

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**Author:** [@ivanlarsen13](https://discourse.julialang.org/u/ivanlarsen13)\
**Replies:** 1\
**Last updated:** [September 27, 2017, 5:28am UTC](https://discourse.julialang.org/t/adding-excel-file-to-jupyter-notebook/6098 "2017-09-27T05:28:33Z")

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Hello, I installed the ExcelReaders package from github, and on Jupyter Notebook I write: using ExcelReaders data = readxlsheet(“http://localhost:8889/view/Desktop/UT%20Austin%20Econ/2nd%20Year/IO/Filename.xlsx”, “She…

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## [How to change value of Nullable{WeakRefString{UInt8}} using CSV package?](https://discourse.julialang.org/t/how-to-change-value-of-nullable-weakrefstring-uint8-using-csv-package/6080)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 4\
**Last updated:** [September 26, 2017, 1:14pm UTC](https://discourse.julialang.org/t/how-to-change-value-of-nullable-weakrefstring-uint8-using-csv-package/6080 "2017-09-26T13:14:00Z")

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Hi ! I try to work with the CSV package and I have some problem to change the value of a DataFrame entry because of the Nullable{WeakRefString{UInt8}} type. I do not know in advance the types of the columns so the defa…

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## [DataFrame : eltypes with variable length](https://discourse.julialang.org/t/dataframe-eltypes-with-variable-length/6016)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 2\
**Last updated:** [September 21, 2017, 10:02am UTC](https://discourse.julialang.org/t/dataframe-eltypes-with-variable-length/6016 "2017-09-21T10:02:00Z")

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Hi, The function readtable(filename, \[keyword options\]) as an optional keyword eltypes::Vector – Specify the types of all columns. Defaults to \[\]. When the exact size of the table, it is possible to specify the type…

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## [Any interest in a JavaScript to julia translating tool?](https://discourse.julialang.org/t/any-interest-in-a-javascript-to-julia-translating-tool/6011)

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**Author:** [@TravisA9](https://discourse.julialang.org/u/TravisA9)\
**Replies:** 0\
**Last updated:** [September 20, 2017, 9:19pm UTC](https://discourse.julialang.org/t/any-interest-in-a-javascript-to-julia-translating-tool/6011 "2017-09-20T21:19:44Z")

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Just wanted to see how much interest there is in having a tool for translating js to jl? Any old js projects you have been meaning to port to julia? …in my case I once made a script to make a really rough translation. I…

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## [Reading and processing Data files concurrently](https://discourse.julialang.org/t/reading-and-processing-data-files-concurrently/5972)

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**Author:** [@Fred](https://discourse.julialang.org/u/Fred)\
**Replies:** 18\
**Last updated:** [September 20, 2017, 8:15pm UTC](https://discourse.julialang.org/t/reading-and-processing-data-files-concurrently/5972 "2017-09-20T20:15:11Z")

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Hi, I have many data files to process (calculate the median of each row and then compare the medians together) and I would like top process them in parallel since the first steps are independent. I tried the following …

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## [JuliaDB problems](https://discourse.julialang.org/t/juliadb-problems/5970)

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**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 2\
**Last updated:** [September 19, 2017, 2:30pm UTC](https://discourse.julialang.org/t/juliadb-problems/5970 "2017-09-19T14:30:36Z")

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I am unable to use JuliaDB. The following says it all: julia\> using JuliaDB julia\> path = Pkg.dir(“home”, “js”, “db\_docs”, “sql”, “projects”, “basic\_sciences”, “juliadb”) “/home/js/.julia/v0.6/home/js/db\_docs/sql/pro…

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## [Best way to get pieces of a parquet into a dataframe](https://discourse.julialang.org/t/best-way-to-get-pieces-of-a-parquet-into-a-dataframe/5949)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 0\
**Last updated:** [September 18, 2017, 3:34pm UTC](https://discourse.julialang.org/t/best-way-to-get-pieces-of-a-parquet-into-a-dataframe/5949 "2017-09-18T15:34:22Z")

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I’m looking for a minimal working example for loading some part of a parquet file into a dataframe and vice versa. I’m assuming that the only way to do this currently is with Spark.jl. Right now I don’t even know if th…

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## [Initialization Error: ODBC](https://discourse.julialang.org/t/initialization-error-odbc/5884)

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**Author:** [@jasoriya](https://discourse.julialang.org/u/jasoriya)\
**Replies:** 1\
**Last updated:** [September 14, 2017, 12:25pm UTC](https://discourse.julialang.org/t/initialization-error-odbc/5884 "2017-09-14T12:25:48Z")

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I am working with Julia 0.5.2 and I added ODBC package Pkg.add ("ODBC") On running Using ODBC I get the following error: LoadError: InitError: ccall: could not find function SQLAllocHandle in library during initi…

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## [Error when grouping using Query.jl](https://discourse.julialang.org/t/error-when-grouping-using-query-jl/5809)

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**Author:** [@innerlee](https://discourse.julialang.org/u/innerlee)\
**Replies:** 1\
**Last updated:** [September 11, 2017, 9:10pm UTC](https://discourse.julialang.org/t/error-when-grouping-using-query-jl/5809 "2017-09-11T21:10:18Z")

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Let the data sourse be a list of Dicts: julia\> as = \[Dict("id" =\> "a", "v" =\> 1), Dict("id" =\> "b", "v" =\> 2)\] Then we group them by id julia\> using Query julia\> @from a in as begin @group a by a…

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## [Comparing DataFrames native API and Query](https://discourse.julialang.org/t/comparing-dataframes-native-api-and-query/5472)

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**Author:** [@piever](https://discourse.julialang.org/u/piever)\
**Replies:** 4\
**Last updated:** [September 1, 2017, 5:57pm UTC](https://discourse.julialang.org/t/comparing-dataframes-native-api-and-query/5472 "2017-09-01T17:57:20Z")

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I’m trying to understand to what extent the functionality of Query.jl can replace data manipulations that are already implemented in the DataFrames.jl. So far I’m impressed with Query’s flexibility, but there are a coupl…

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## [Combining MySQL and Query](https://discourse.julialang.org/t/combining-mysql-and-query/5627)

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**Author:** [@piever](https://discourse.julialang.org/u/piever)\
**Replies:** 4\
**Last updated:** [August 31, 2017, 11:24pm UTC](https://discourse.julialang.org/t/combining-mysql-and-query/5627 "2017-08-31T23:24:23Z")

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Is there a way to execute a Query.jl style Query directly on a MySQL database? Given that MySQL.jl gives an iterable tuple wiht MySQLRowIterator(con, command) I thought something like this could work: @from i in MySQLRo…

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## [I want to extract and convert to integer a column in a DataFrame](https://discourse.julialang.org/t/i-want-to-extract-and-convert-to-integer-a-column-in-a-dataframe/5566)

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**Author:** [@Jean-Victor](https://discourse.julialang.org/u/Jean-Victor)\
**Replies:** 8\
**Last updated:** [August 26, 2017, 7:00pm UTC](https://discourse.julialang.org/t/i-want-to-extract-and-convert-to-integer-a-column-in-a-dataframe/5566 "2017-08-26T19:00:02Z")

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With Julia 0.5, I could do this: Calories=int(Nutrition\[2:11,2\]), where Nutrition is a DataFrame. With Julia 0.6, whatever I do of the kind spawns an ominous red box which floats over my program like a giant cloud in a…

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## [How to dynamically call a column in a @where macro?](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [August 23, 2017, 12:27pm UTC](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503 "2017-08-23T12:27:20Z")

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How can I dynamically refer to a column name (i.e., a Symbol) within a @where macro ? using DataFrames, DataFramesMeta df = DataFrame(x=Int64\[1,2,3,4,5\]) name = "x" nameS = Symbol(name) df2 = @where(df, :x .\>= 2) …

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## [ODBC query is slow because of casting to a GUID type](https://discourse.julialang.org/t/odbc-query-is-slow-because-of-casting-to-a-guid-type/5383)

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**Author:** [@swt30](https://discourse.julialang.org/u/swt30)\
**Replies:** 2\
**Last updated:** [August 22, 2017, 10:18am UTC](https://discourse.julialang.org/t/odbc-query-is-slow-because-of-casting-to-a-guid-type/5383 "2017-08-22T10:18:58Z")

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I’m reading in some moderately-sized tables (10^3–10^6 rows) from a PostgreSQL database. Because PostgreSQL.jl seems to be dead on v0.6, I’ve had to resort to installing the Postgres ODBC driver and using ODBC.jl. I’m pr…

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## [Should view(array, 1:length(array)) return a SubArray?](https://discourse.julialang.org/t/should-view-array-1-length-array-return-a-subarray/5449)

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**Author:** [@sambitdash](https://discourse.julialang.org/u/sambitdash)\
**Replies:** 11\
**Last updated:** [August 19, 2017, 3:33am UTC](https://discourse.julialang.org/t/should-view-array-1-length-array-return-a-subarray/5449 "2017-08-19T03:33:35Z")

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Hi All, julia\> arr = zeros(Int, 3) 3-element Array{Int64,1}: 0 0 0 julia\> b = view(arr, 1:length(arr)) 3-element SubArray{Int64,1,Array{Int64,1},Tuple{UnitRange{Int64}},true}: 0 0 0 Now that b will be treated li…

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## [How do you save data in Monte Carlo simulations?](https://discourse.julialang.org/t/how-do-you-save-data-in-monte-carlo-simulations/5403)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 8\
**Last updated:** [August 16, 2017, 6:03am UTC](https://discourse.julialang.org/t/how-do-you-save-data-in-monte-carlo-simulations/5403 "2017-08-16T06:03:08Z")

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Let’s say I have a prior made of continuous and discrete variables: using Distributions a = Uniform() b = Normal() c = Binomial() ... I generate random numbers from the prior, input them into an expensive model and th…

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## [Print dataframe in HTML](https://discourse.julialang.org/t/print-dataframe-in-html/5319)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 2\
**Last updated:** [August 10, 2017, 5:24pm UTC](https://discourse.julialang.org/t/print-dataframe-in-html/5319 "2017-08-10T17:24:50Z")

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I have a type that has as one of its fields a AbstractDataFrame: struct GeoDataFrame{DF\<:AbstractDataFrame} data::DF coordnames::Vector{Symbol} end This is how I print the object in plain text: # compact show Base…

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## [Memory leak and JLD, does anyone maintain the package?](https://discourse.julialang.org/t/memory-leak-and-jld-does-anyone-maintain-the-package/5298)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 2\
**Last updated:** [August 9, 2017, 11:35am UTC](https://discourse.julialang.org/t/memory-leak-and-jld-does-anyone-maintain-the-package/5298 "2017-08-09T11:35:55Z")

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Hi, I would like to ask, of someone is maintaining JLD package. There is an open issue https://github.com/JuliaIO/JLD.jl/issues/100 Memory leak when loading multiple arrays in Julia 0.5 more than half a year, which I…

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## [How to wrap DataFrame \[\] operator?](https://discourse.julialang.org/t/how-to-wrap-dataframe-operator/5267)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 1\
**Last updated:** [August 7, 2017, 8:52pm UTC](https://discourse.julialang.org/t/how-to-wrap-dataframe-operator/5267 "2017-08-07T20:52:57Z")

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I have a type that wraps a AbstractDataFrame, and I am interested in defining a method that just forwards the \[\] operator: struct GeoData{DF\<:AbstractDataFrame} data::DF coordnames::Vector{Symbol} end How to make c…

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## [Grouping a DataFrame by something other than an existing column](https://discourse.julialang.org/t/grouping-a-dataframe-by-something-other-than-an-existing-column/5246)

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**Author:** [@Seth\_Chandler](https://discourse.julialang.org/u/Seth_Chandler)\
**Replies:** 2\
**Last updated:** [August 6, 2017, 1:49pm UTC](https://discourse.julialang.org/t/grouping-a-dataframe-by-something-other-than-an-existing-column/5246 "2017-08-06T13:49:37Z")

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Is it possible to group a DataFrame by something other than an existing column? Yes, I could add a column to the DataFrame that contains the computed values and then group on that new column. But this may clutter the Da…

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## [How to assign subsets of a large dataset into different arrays within a loop](https://discourse.julialang.org/t/how-to-assign-subsets-of-a-large-dataset-into-different-arrays-within-a-loop/5218)

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**Author:** [@Devi\_Sree](https://discourse.julialang.org/u/Devi_Sree)\
**Replies:** 1\
**Last updated:** [August 4, 2017, 8:27am UTC](https://discourse.julialang.org/t/how-to-assign-subsets-of-a-large-dataset-into-different-arrays-within-a-loop/5218 "2017-08-04T08:27:47Z")

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I am using for loop that divides a large array say arr and assign the subsets into arrays arr1, arr2.. I am stuck at assigning subsets to arrays within a loop. My whole datastet arr contains 5 rows and 5 columns. …

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## [Which approach for multidimensional computation?](https://discourse.julialang.org/t/which-approach-for-multidimensional-computation/5182)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 7\
**Last updated:** [August 3, 2017, 2:47pm UTC](https://discourse.julialang.org/t/which-approach-for-multidimensional-computation/5182 "2017-08-03T14:47:21Z")

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Hello, I need to make a multi-dimension computation, specifically V\_{ft,dc,r,t+1} = V\_{ft,dc,r,t} \*(1-m\_{ft,dc,r,t} - 1/tp\_{ft,dc,r,t}) + V\_{ft\_,dc-1,r,t}\*tp\_{ft,dc-1,r,t}\*\\beta\_{ft,dc,r,t} where, if you are curious…

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## [One sided formula & ModelMatrix](https://discourse.julialang.org/t/one-sided-formula-modelmatrix/5102)

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**Author:** [@clinton](https://discourse.julialang.org/u/clinton)\
**Replies:** 0\
**Last updated:** [July 28, 2017, 3:10am UTC](https://discourse.julialang.org/t/one-sided-formula-modelmatrix/5102 "2017-07-28T03:10:25Z")

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I’m trying to write some 2SLS code, and ran into the following scenarios: I have a one-sided formula and a DataFrame. Is there a simple way to get the model matrix given that formula? The @formula macro throws an error …

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## [Creating custom DataFrame types](https://discourse.julialang.org/t/creating-custom-dataframe-types/4992)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [July 21, 2017, 2:55pm UTC](https://discourse.julialang.org/t/creating-custom-dataframe-types/4992 "2017-07-21T14:55:46Z")

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I am putting some effort to include a special DataFrame type in my package that tracks columns representing spatial coordinates: struct GeoData data::AbstractDataFrame coordnames::Vector{Symbol} end I can then defi…

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## [Query.jl: Automatize multiple @select at once](https://discourse.julialang.org/t/query-jl-automatize-multiple-select-at-once/4948)

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**Author:** [@kaslusimoes](https://discourse.julialang.org/u/kaslusimoes)\
**Replies:** 5\
**Last updated:** [July 20, 2017, 5:37pm UTC](https://discourse.julialang.org/t/query-jl-automatize-multiple-select-at-once/4948 "2017-07-20T17:37:47Z")

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Suppose I have a DataFrame with a great number of fields and the number of these columns I want to select using Query.jl. is also large. Is there any way to automatize this? For example, I have a vector v naming the fie…

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