# \#csv **URL:** https://forum.elixirforum.com/tag/csv/679.md [Latest](https://forum.elixirforum.com/latest.md) · [Categories](https://forum.elixirforum.com/categories.md) · [Tags](https://forum.elixirforum.com/tags.md) --- ## [Glazer - the Swiss Army knife of JSON / YAML / CSV parsing](https://forum.elixirforum.com/t/glazer-the-swiss-army-knife-of-json-yaml-csv-parsing/75640)
**Author:** [@saleyn](https://forum.elixirforum.com/u/saleyn)\ **Replies:** 10\ **Last updated:** [August 25, 2026, 2:14pm UTC](https://forum.elixirforum.com/t/glazer-the-swiss-army-knife-of-json-yaml-csv-parsing/75640 "2026-08-25T14:14:31Z")
glazer started as a blazing-fast NIF JSON codec (single-pass, straight to/from native terms - no AST). In 0.3.0, the same engine now parses and encodes YAML and CSV too. The numbers: JSON: faster encoding than everyt… --- ## [RustyCSV - NimbleCSV-compatible CSV parsing and encoding with Rust NIFs](https://forum.elixirforum.com/t/rustycsv-nimblecsv-compatible-csv-parsing-and-encoding-with-rust-nifs/76362)
**Author:** [@jeffyzooom](https://forum.elixirforum.com/u/jeffyzooom)\ **Replies:** 3\ **Last updated:** [August 15, 2026, 1:50am UTC](https://forum.elixirforum.com/t/rustycsv-nimblecsv-compatible-csv-parsing-and-encoding-with-rust-nifs/76362 "2026-08-15T01:50:04Z")
Hi all, I’ve been working on RustyCSV, a CSV parser and encoder for Elixir backed by Rust NIFs. Version 0.4.0 is now available. The goal is to provide a drop-in replacement for NimbleCSV 1.3.0 for both parsing and enco… --- ## [Huge CSV processing that needs to be processed hourly - any tips?](https://forum.elixirforum.com/t/huge-csv-processing-that-needs-to-be-processed-hourly-any-tips/28307)
**Author:** [@Blokh](https://forum.elixirforum.com/u/Blokh)\ **Replies:** 5\ **Last updated:** [August 14, 2026, 3:26pm UTC](https://forum.elixirforum.com/t/huge-csv-processing-that-needs-to-be-processed-hourly-any-tips/28307 "2026-08-14T15:26:42Z")
Hey guys, I’ve got a huge CSV ( around 10 GB ) that needs to be processed hourly Do you guys have any suggestions what is the best practice in that scenario? Any useful mixes? Thanks in advance. Daniel --- ## [Howto set the decimal separator when reading with CSV.decode() or Explorer.DataFrame.load\_csv()](https://forum.elixirforum.com/t/howto-set-the-decimal-separator-when-reading-with-csv-decode-or-explorer-dataframe-load-csv/69240)
**Author:** [@GordianGo](https://forum.elixirforum.com/u/GordianGo)\ **Replies:** 7\ **Last updated:** [February 13, 2025, 2:34pm UTC](https://forum.elixirforum.com/t/howto-set-the-decimal-separator-when-reading-with-csv-decode-or-explorer-dataframe-load-csv/69240 "2025-02-13T14:34:29Z")
Hi, my csv file that i want to read is from DE-region (Germany). There they use comma as decimal separator for floating point numbers. eg 4,58 Unfortunately I cannot identitfy a parameter in the documentation to specif… --- ## [Explorer.DataFrame.from\_csv problem](https://forum.elixirforum.com/t/explorer-dataframe-from-csv-problem/69321)
**Author:** [@evadne](https://forum.elixirforum.com/u/evadne)\ **Replies:** 3\ **Last updated:** [February 11, 2025, 2:24am UTC](https://forum.elixirforum.com/t/explorer-dataframe-from-csv-problem/69321 "2025-02-11T02:24:07Z")
Hi all I have some issues reading nanosecond precision timestamps in CSVs using latest explorer. Repro as follows: ./script/ingestion\_test.csv datetime\_ns 1738573413286629810 ./script/ingestion\_test.exs Mix.install… --- ## [\`CSV.encode\` float values are automatically converted scientific notation](https://forum.elixirforum.com/t/csv-encode-float-values-are-automatically-converted-scientific-notation/65632)
**Author:** [@lucilawho](https://forum.elixirforum.com/u/lucilawho)\ **Replies:** 0\ **Last updated:** [August 22, 2024, 7:26pm UTC](https://forum.elixirforum.com/t/csv-encode-float-values-are-automatically-converted-scientific-notation/65632 "2024-08-22T19:26:52Z")
CSV.encode float values are automatically converted scientific notation When I do CSV.encode(7900.00) I get \["7.9e3\\r\\n"\] instead of \["7900.00\\r\\n"\] I’ve checked CSV docs (v3.2.1) and CSV code but I can’t figure out … --- ## [How do I know when Finch.stream has finished fetching data?](https://forum.elixirforum.com/t/how-do-i-know-when-finch-stream-has-finished-fetching-data/63217)
**Author:** [@m\_tofi](https://forum.elixirforum.com/u/m_tofi)\ **Replies:** 8\ **Last updated:** [May 2, 2024, 12:02pm UTC](https://forum.elixirforum.com/t/how-do-i-know-when-finch-stream-has-finished-fetching-data/63217 "2024-05-02T12:02:52Z")
I am using Finch.stream to fetch a large CSV file from a server, but neither the ‘done’ state nor the ‘error’ state is being triggered when I use "{:halt, {:error, reason}}". I need help figuring out how to determine whe… --- ## [Cannot figure out NimbleCSV parser](https://forum.elixirforum.com/t/cannot-figure-out-nimblecsv-parser/60698)
**Author:** [@hassamullah](https://forum.elixirforum.com/u/hassamullah)\ **Replies:** 2\ **Last updated:** [January 1, 2024, 7:04am UTC](https://forum.elixirforum.com/t/cannot-figure-out-nimblecsv-parser/60698 "2024-01-01T07:04:06Z")
In the first code snippet in the NimbleCSV Docs NimbleCSV.define(MyParser, separator: “\\t”, escape: “"”) I don’t know where the MyParser variable comes form, kindly guide me FYI, I’m new to elixir and still figuring… --- ## [Form phx-change don't work after csv download](https://forum.elixirforum.com/t/form-phx-change-dont-work-after-csv-download/58977)
**Author:** [@Valeriy](https://forum.elixirforum.com/u/Valeriy)\ **Replies:** 8\ **Last updated:** [October 18, 2023, 7:10am UTC](https://forum.elixirforum.com/t/form-phx-change-dont-work-after-csv-download/58977 "2023-10-18T07:10:40Z")
Hi guys! I try CSV Export with Phoenix and LiveView with this guide CSV Export with Phoenix and LiveView - Tutorials and screencasts for Elixir, Phoenix and LiveView (fullstackphoenix.com). I use filters for data displ… --- ## [No function clause matching in CSV.Decoding.Preprocessing.Lines.starts\_sequence?/5](https://forum.elixirforum.com/t/no-function-clause-matching-in-csv-decoding-preprocessing-lines-starts-sequence-5/51080)
**Author:** [@docjazither](https://forum.elixirforum.com/u/docjazither)\ **Replies:** 6\ **Last updated:** [September 18, 2023, 2:27pm UTC](https://forum.elixirforum.com/t/no-function-clause-matching-in-csv-decoding-preprocessing-lines-starts-sequence-5/51080 "2023-09-18T14:27:08Z")
Hey OGs, I have a function that loads csv files into my app. When my user used special characters, it failed they used name like: Zoë Here is my function: defp read(csv) do csv.path |\> Path.expand() |\> Fi… --- ## [Error when importing CSV with Explorer.DataFrame.from\_csv! possibly related to dtype](https://forum.elixirforum.com/t/error-when-importing-csv-with-explorer-dataframe-from-csv-possibly-related-to-dtype/54776)
**Author:** [@alphydan](https://forum.elixirforum.com/u/alphydan)\ **Replies:** 17\ **Last updated:** [March 25, 2023, 2:33pm UTC](https://forum.elixirforum.com/t/error-when-importing-csv-with-explorer-dataframe-from-csv-possibly-related-to-dtype/54776 "2023-03-25T14:33:54Z")
Hello, I’m an elixir beginner, exploring livebook. I’m running a local notebook on a linux machine. Initially I tried to import a CSV file with Explorer like so: alias Explorer.{DataFrame, Series} path\_to\_csv = "./som… --- ## [Best way to read data in the most performant way from multiple large CSV files?](https://forum.elixirforum.com/t/best-way-to-read-data-in-the-most-performant-way-from-multiple-large-csv-files/54432)
**Author:** [@raza\_ep](https://forum.elixirforum.com/u/raza_ep)\ **Replies:** 6\ **Last updated:** [March 14, 2023, 7:43am UTC](https://forum.elixirforum.com/t/best-way-to-read-data-in-the-most-performant-way-from-multiple-large-csv-files/54432 "2023-03-14T07:43:32Z")
My objective is to read data (in the most performant approach) from multiple large CSV files, make minimal transformations and eventually write to output files. I want to ensure I am leveraging all the compute on my mach… --- ## [Stream CSV file from a remote zip on S3](https://forum.elixirforum.com/t/stream-csv-file-from-a-remote-zip-on-s3/45912)
**Author:** [@fchabouis](https://forum.elixirforum.com/u/fchabouis)\ **Replies:** 8\ **Last updated:** [February 15, 2023, 1:41pm UTC](https://forum.elixirforum.com/t/stream-csv-file-from-a-remote-zip-on-s3/45912 "2023-02-15T13:41:37Z")
I have a zip file, containing CSVs, on a remote S3 cellar. Using Unzip, I can get a stream of the CSV file that I would like to decode, like so : aws\_s3\_config = ExAws.Config.new(:s3, access\_key\_id: \[… --- ## [Rename all map keys](https://forum.elixirforum.com/t/rename-all-map-keys/48478)
**Author:** [@iamacube](https://forum.elixirforum.com/u/iamacube)\ **Replies:** 6\ **Last updated:** [August 9, 2022, 4:45pm UTC](https://forum.elixirforum.com/t/rename-all-map-keys/48478 "2022-08-09T16:45:34Z")
Hi! I have a list of maps and I want to rename the keys. What I have: \[info\] entities: \[ok: %{"Email Address \[Required\]" =\> "fblue@mikasa.com", "First Name \[Required\]" =\> "Blue", "Last Name \[Required\]" =\> "First"}, ok:… --- ## [Podcast: ThinkingElixir 104 - Exploring Our Data with Chris Grainger](https://forum.elixirforum.com/t/podcast-thinkingelixir-104-exploring-our-data-with-chris-grainger/48489)
**Author:** [@brainlid](https://forum.elixirforum.com/u/brainlid)\ **Replies:** 0\ **Last updated:** [June 21, 2022, 12:18pm UTC](https://forum.elixirforum.com/t/podcast-thinkingelixir-104-exploring-our-data-with-chris-grainger/48489 "2022-06-21T12:18:31Z")
In episode 104 of Thinking Elixir, Chris Grainger explains Explorer, Nx’s recent addition. It’s a “Data Frame” library which sounds far more nebulous than it is. It lets us explore and manipulate two-dimensional data lik… --- ## [Phoenix json API extremely slow when serving CSV files](https://forum.elixirforum.com/t/phoenix-json-api-extremely-slow-when-serving-csv-files/43893)
**Author:** [@quda](https://forum.elixirforum.com/u/quda)\ **Replies:** 48\ **Last updated:** [November 19, 2021, 12:34pm UTC](https://forum.elixirforum.com/t/phoenix-json-api-extremely-slow-when-serving-csv-files/43893 "2021-11-19T12:34:34Z")
I am building a json REST API with Phoenix that (among other services) has to convert static CSV files from a repository and “serve” them as response in json format; that will be used downstream by other services in our … --- ## [Catalog - compile time content processing engine for markdown, json, yaml, and more](https://forum.elixirforum.com/t/catalog-compile-time-content-processing-engine-for-markdown-json-yaml-and-more/41806)
**Author:** [@kevinlang](https://forum.elixirforum.com/u/kevinlang)\ **Replies:** 0\ **Last updated:** [August 20, 2021, 4:01pm UTC](https://forum.elixirforum.com/t/catalog-compile-time-content-processing-engine-for-markdown-json-yaml-and-more/41806 "2021-08-20T16:01:37Z")
Hey all, I created a library that allows you to easily process your content or data files at compile time, Catalog. It works off of the same root idea as NimblePublisher, but expanded a bit to work with a wider array of… --- ## [Replacing placeholders in a string from CSV values](https://forum.elixirforum.com/t/replacing-placeholders-in-a-string-from-csv-values/40390)
**Author:** [@hakarabakara](https://forum.elixirforum.com/u/hakarabakara)\ **Replies:** 15\ **Last updated:** [June 13, 2021, 6:16pm UTC](https://forum.elixirforum.com/t/replacing-placeholders-in-a-string-from-csv-values/40390 "2021-06-13T18:16:38Z")
Hi, My application accepts a string input and dynamic values from an uploaded CSV file and should generate a response based on the csv. The string has placeholders have corresponding values in the CSV under the headers… --- ## [Reusing compile time code](https://forum.elixirforum.com/t/reusing-compile-time-code/38819)
**Author:** [@Fl4m3Ph03n1x](https://forum.elixirforum.com/u/Fl4m3Ph03n1x)\ **Replies:** 15\ **Last updated:** [April 9, 2021, 12:09pm UTC](https://forum.elixirforum.com/t/reusing-compile-time-code/38819 "2021-04-09T12:09:29Z")
Background I have to read a CSV and currently this is happening at compile time as the function runs in a module attribute: # Imagine this csv file has 3 columns "sport, country, league" @csv\_sports\_data :my\_app |\> … --- ## [Csv2Sql - Load csv files to database(Web UI and Postgres Support)](https://forum.elixirforum.com/t/csv2sql-load-csv-files-to-database-web-ui-and-postgres-support/35580)
**Author:** [@arpan](https://forum.elixirforum.com/u/arpan)\ **Replies:** 0\ **Last updated:** [November 16, 2020, 11:28am UTC](https://forum.elixirforum.com/t/csv2sql-load-csv-files-to-database-web-ui-and-postgres-support/35580 "2020-11-16T11:28:01Z")
CSV2SQL - Blazing fast csv to database loader! Hi, I have been working on a side project for quite some time now. I had earlier posted about this project here, since then I have improved the codebase and I have added so… --- ## [File encoding detection library](https://forum.elixirforum.com/t/file-encoding-detection-library/34972)
**Author:** [@patryk.it](https://forum.elixirforum.com/u/patryk.it)\ **Replies:** 12\ **Last updated:** [October 18, 2020, 2:47pm UTC](https://forum.elixirforum.com/t/file-encoding-detection-library/34972 "2020-10-18T14:47:48Z")
Hi guys! My question is related to the file encoding topic. I’m working on a feature that allows users to upload a CSV file that might be in different charset. It’s not only about UTF-8 and I need to detect given encodi… --- ## [Streaming from Ecto, through CSV, Zip, then up to S3... w/o going through a temp file](https://forum.elixirforum.com/t/streaming-from-ecto-through-csv-zip-then-up-to-s3-w-o-going-through-a-temp-file/30215)
**Author:** [@jc00ke](https://forum.elixirforum.com/u/jc00ke)\ **Replies:** 9\ **Last updated:** [March 30, 2020, 8:19pm UTC](https://forum.elixirforum.com/t/streaming-from-ecto-through-csv-zip-then-up-to-s3-w-o-going-through-a-temp-file/30215 "2020-03-30T20:19:08Z")
Hi there, I’ve got a data export that has the following flow: I’m using Ecto, CSV.encode/2, Zstream.zip/2 and ExAws.S3.Upload.stream\_file/2. I tried at first to avoid the temp file (I’m on Heroku, so not entirely i… --- ## [Library for exporting CSV](https://forum.elixirforum.com/t/library-for-exporting-csv/14346)
**Author:** [@Rakakku](https://forum.elixirforum.com/u/Rakakku)\ **Replies:** 4\ **Last updated:** [March 25, 2020, 6:02am UTC](https://forum.elixirforum.com/t/library-for-exporting-csv/14346 "2020-03-25T06:02:43Z")
I need to read data from a database, process and transform it and send to a user in CSV. I’ve found 2 libraries for far: csv and nimble\_csv. Both look decent. Among those 2 or among others, what would you recommend? O… --- ## [DataQuacker - a library for parsing non-sandboxed data like CSV files](https://forum.elixirforum.com/t/dataquacker-a-library-for-parsing-non-sandboxed-data-like-csv-files/24642)
**Author:** [@fiodorbaczynski](https://forum.elixirforum.com/u/fiodorbaczynski)\ **Replies:** 0\ **Last updated:** [August 13, 2019, 11:06am UTC](https://forum.elixirforum.com/t/dataquacker-a-library-for-parsing-non-sandboxed-data-like-csv-files/24642 "2019-08-13T11:06:13Z")
Hi all, I often find it tedious to parse CSV files. There are often complex rules for validating and transforming the data, matching columns by their indexes or header values, etc. Sometimes there is also a need to map … --- ## [How to parse CSV into typed terms?](https://forum.elixirforum.com/t/how-to-parse-csv-into-typed-terms/22553)
**Author:** [@marcin](https://forum.elixirforum.com/u/marcin)\ **Replies:** 5\ **Last updated:** [May 21, 2019, 1:04am UTC](https://forum.elixirforum.com/t/how-to-parse-csv-into-typed-terms/22553 "2019-05-21T01:04:05Z")
Hi! I’d like to parse a CSV rows into typed elements, without knowing what is the schema (column order) of the CSV. In ruby the CSV library will parse strings into types. In Elixir, both csv and nimble\_csv libraries pr… --- ## [How to generate a big CSV file concurrently?](https://forum.elixirforum.com/t/how-to-generate-a-big-csv-file-concurrently/20159)
**Author:** [@sabri](https://forum.elixirforum.com/u/sabri)\ **Replies:** 7\ **Last updated:** [February 16, 2019, 1:12pm UTC](https://forum.elixirforum.com/t/how-to-generate-a-big-csv-file-concurrently/20159 "2019-02-16T13:12:41Z")
Hello I need to generate a big CSV file, that might has thousands of entries, how can I run concurrent processes to handle this task and all write to the resulted file at the same time? Is there an advice? what is the … --- ## [Nested list value inside map csv export](https://forum.elixirforum.com/t/nested-list-value-inside-map-csv-export/19532)
**Author:** [@script](https://forum.elixirforum.com/u/script)\ **Replies:** 4\ **Last updated:** [January 19, 2019, 12:10pm UTC](https://forum.elixirforum.com/t/nested-list-value-inside-map-csv-export/19532 "2019-01-19T12:10:00Z")
The code is working fine it takes list of maps convert them into csv and export the value. This is the code def to\_csv(map, path) do file = File.open!(path, \[:write, :utf8\]) map |\> IO.inspect() |\> CSV.encode(h… --- ## [How to handle background jobs with elixir/phoenix](https://forum.elixirforum.com/t/how-to-handle-background-jobs-with-elixir-phoenix/16797)
**Author:** [@beto](https://forum.elixirforum.com/u/beto)\ **Replies:** 11\ **Last updated:** [September 26, 2018, 9:39pm UTC](https://forum.elixirforum.com/t/how-to-handle-background-jobs-with-elixir-phoenix/16797 "2018-09-26T21:39:58Z")
Hello, I am working on an task, that requires to parse a csv sent from a react frontend. When the backend receives it, it should make an API call to a webservice. But now the csv is large and it’s not functional. My idea… --- ## [Read a CSV file and convert it into list of tuples](https://forum.elixirforum.com/t/read-a-csv-file-and-convert-it-into-list-of-tuples/16596)
**Author:** [@azbshiri](https://forum.elixirforum.com/u/azbshiri)\ **Replies:** 2\ **Last updated:** [September 14, 2018, 1:09pm UTC](https://forum.elixirforum.com/t/read-a-csv-file-and-convert-it-into-list-of-tuples/16596 "2018-09-14T13:09:49Z")
Hey, I wanted to read a CSV file and convert it into a list of tuples and I come up with this: "./pairs.csv" |\> Path.expand(\_\_DIR\_\_) |\> File.stream! |\> Stream.drop(1) |\> Stream.map(&String.trim(&1, "… --- ## [wtUTF8 - encoding issues reading CSV file](https://forum.elixirforum.com/t/wtutf8-encoding-issues-reading-csv-file/204)
**Author:** [@ejc123](https://forum.elixirforum.com/u/ejc123)\ **Replies:** 11\ **Last updated:** [August 29, 2018, 1:27pm UTC](https://forum.elixirforum.com/t/wtutf8-encoding-issues-reading-csv-file/204 "2018-08-29T13:27:30Z")
I don’t think this should be under ‘Advanced’, as I’m definitely not advanced :wink: Sorry for the length, but I’ve tried a bunch of things – everything I can think of. I’ve been attempting to read in a CSV file. I fo… [Next page](https://forum.elixirforum.com/tag/csv/679.md?match_all_tags=true&page=1&tags%5B%5D=csv)