["javascript","python"]
Python Pandas equivalent in JavaScript

With this CSV example: Source,col1,col2,col3 foo,1,2,3 bar,3,4,5 The standard method I use Pandas is this: Parse CSV Select columns into a data frame (col1 and col3) Process the column (e.g. avarage the values of col1 and col3) Is there a JavaScript library that does that like Pandas?
This wiki will summarize and compare many pandas-like Javascript libraries. In general, you should check out the d3 JavaScript library. d3 is very useful "swiss army knife" for handling data in JavaScript, just like pandas is helpful for Python. You may see d3 used frequently like pandas, even if d3 is not exactly a DataFrame/Pandas replacement (i.e. d3 doesn't have the same API; d3 does not have Series / DataFrame classes with methods that match the pandas behavior). Ahmed's answer explains how d3 can be used to achieve some DataFrame functionality, and some of the libraries below were inspired by things like LearnJsData which uses d3 and lodash. As for DataFrame-style data transformation (splitting, joining, group by etc), here is a quick list of some of the JavaScript libraries. Note the libraries are written in different languages, including... browser-compatible aka client-side JavaScript Node.js aka Server-side JavaScript Typescript Some even use CPython transpiled to WebAssembly (but work with Node.js and/or browsers) ...so use the option that's right for you: Pyodide (browser-support AND Nodejs-support) A new but very strong contender from Ahmed Fasih's answer WebAssembly transpilation of CPython and a large portion of the numeric Python ecosystem ("including NumPy, pandas, SciPy, Matplotlib, and scikit-learn") "for the browser and Node.js " made by folks tightly connected to Project Jupyter see its list of included packages danfo-js (browser-support AND NodeJS-support) From Vignesh's answer danfo (which is often imported and aliased as dfd); has a basic DataFrame-type data structure, with the ability to plot directly Built by the team at Tensorflow: "One of the main goals of Danfo.js is to bring data processing, machine learning and AI tools to JavaScript developers. ... Open-source libraries like Numpy and Pandas..." pandas is built on top of numpy; likewise danfo-js is built on tensorflow-js please note danfo may not (yet?) support multi-column indexes pandas-js UPDATE The pandas-js repo has not been updated in awhile From STEEL and Feras' answers "pandas.js is an open source (experimental) library mimicking the Python pandas library. It relies on Immutable.js as the NumPy logical equivalent. The main data objects in pandas.js are, like in Python pandas, the Series and the DataFrame." dataframe-js "DataFrame-js provides an immutable data structure for javascript and datascience, the DataFrame, which allows to work on rows and columns with a sql and functional programming inspired api." data-forge Seen in Ashley Davis' answer "JavaScript data transformation and analysis toolkit inspired by Pandas and LINQ." Note the old data-forge JS repository is no longer maintained; now a new repository uses Typescript jsdataframe "Jsdataframe is a JavaScript data wrangling library inspired by data frame functionality in R and Python Pandas." dataframe "explore data by grouping and reducing." SQL Frames "DataFrames meet SQL, in the Browser" "SQL Frames is a low code data management framework that can be directly embedded in the browser to provide rich data visualization and UX. Complex DataFrames can be composed using familiar SQL constructs. With its powerful built-in analytics engine, data sources can come in any shape, form and frequency and they can be analyzed directly within the browser. It allows scaling to big data backends by transpiling the composed DataFrame logic to SQL." Jandas (browser- AND NodeJS-support; a new TypeScript library developed in 2023) Indexing and query very similar to Pandas Negative number and range indexing Support DataFrame with zero rows/columns Support index with duplicated values iterrows, sort_values, groupby and element-wise operation Then after coming to this question, checking other answers here and doing more searching, I found options like: Apache Arrow in JS Thanks to user Back2Basics suggestion: "Apache Arrow is a columnar memory layout specification for encoding vectors and table-like containers of flat and nested data. Apache Arrow is the emerging standard for large in-memory columnar data (Spark, Pandas, Drill, Graphistry, ...)" polars Polars is a blazingly fast DataFrames library implemented in Rust using Apache Arrow Columnar Format as memory model. Observable At first glance, seems like a JS alternative to the IPython/Jupyter "notebooks" Observable's page promises: "Reactive programming", a "Community", on a "Web Platform" See 5 minute intro here portal.js (formerly recline; from Rufus' answer) MAY BE OUTDATED: Does not use a "DataFrame" API MAY BE OUTDATED: Instead emphasizes its "Multiview" (the UI) API, (similar to jQuery/DOM model) which doesn't require jQuery but does require a browser! More examples MAY BE OUTDATED: Also emphasizes its MVC-ish architecture; including back-end stuff (i.e. database connections) js-data Really more of an ORM! Most of its modules correspond to different data storage questions (js-data-mongodb, js-data-redis, js-data-cloud-datastore), sorting, filtering, etc. On plus-side does work on Node.js as a first-priority; "Works in Node.js and in the Browser." miso (another suggestion from Rufus) Impressive backers like Guardian and bocoup. AlaSQL "AlaSQL" is an open source SQL database for Javascript with a strong focus on query speed and data source flexibility for both relational data and schemaless data. It works in your browser, Node.js, and Cordova." Some thought experiments: "Scaling a DataFrame in Javascript" - Gary Sieling Here are the criteria we used to consider the above choices General Criteria Language (NodeJS vs browser JS vs Typescript) Dependencies (i.e. if it uses an underlying library / AJAX/remote API's) Actively supported (active user-base, active source repository, etc) Size/speed of JS library Panda's criterias in its R comparison Performance Functionality/flexibility Ease-of-use Similarity to Pandas / Dataframe API's Specifically hits on their main features Data-science emphasis Built-in visualization functions Demonstrated integration in combination with other tools like Jupyter (interactive notebooks), etc