zsv+lib is a fast CSV parser library and extensible command-line utility. It achieves high performance using SIMD operations, efficient memory use and other optimization techniques.
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Preliminary performance results compare favorably vs other CSV utilities (xsv
,
tsv-utils
, csvkit
, mlr
(miller) etc). Below were results on a pre-M1 OSX
MBA; on most platforms zsvlib was 2x faster, though in some cases the advantage
was as small as 20% (see also M1 update note below) (mlr not shown as it was
about 25x slower):
** See 12/19 update re M1 processor at https://github.com/liquidaty/zsv/blob/main/app/benchmark/README.md.
zsv
is an extensible CSV utility, which uses zsvlib, for tasks such as slicing
and dicing, querying with SQL, combining, serializing, flattening,
converting between CSV/JSON/sqlite3 and more.
zsv
is streamlined for easy development of custom dynamic extensions.
zsvlib and zsv
are written in C, but since zsvlib is a library, and zsv
extensions are just shared libraries, you can extend zsv
with your own code in
any programming language, so long as it has been compiled into a shared library
that implements the expected
interface.
- Available as BOTH a library and an application
- Open-source, permissively licensed
- Handles real-world CSV the same way that spreadsheet programs do (including edge cases). Gracefully handles (and can "clean") real-world data that may be "dirty"
- Runs on OSX (tested on clang/gcc), Linux (gcc), Windows (mingw), BSD (gcc-only) and in-browser (emscripten/wasm)
- Fast (maybe the fastest ever, at least on all platforms we've benchmarked where 256 SIMD operations are available). See app/benchmark/README.md
- Low memory usage (regardless of how big your data is) and size footprint for both lib (~20k) and CLI executable (< 1MB)
- Easy to use as a library in a few lines of code
- Includes
zsv
CLI with built-in commands:select
,count
,sql
query,describe
,flatten
,serialize
,2json
,2db
,stack
,pretty
,2tsv
,jq
- easily convert between CSV/JSON/sqlite3
- CLI is easy to extend/customize with a few lines of code via modular plug-in framework. Just write a few custom functions and compile into a distributable DLL that any existing zsv installation can use
- zsvlib and
zsv
are permissively licensed
zsv is available from a number of package managers (IN PROGRESS):
- OSX:
brew install zsv
- Windows:
nuget install zsv
- Linux:
yum install zsv
Download pre-built binaries and packages for OSX, Windows, Linux and BSD from the Releases page.
You can also download pre-built binaries and packages from Actions for the latest commits and PRs but these are retained only for limited days.
brew tap liquidaty/zsv
brew install zsv
For Linux (Debian/Ubuntu - *.deb
):
# Install
sudo apt install ./zsv-amd64-linux-gcc.deb
# Uninstall
sudo apt remove zsv
For Linux (RHEL/CentOS - *.rpm
):
# Install
sudo yum install ./zsv-amd64-linux-gcc.rpm
# Uninstall
sudo yum remove zsv
For Windows (*.nupkg
), install with nuget.exe
:
# Install via nuget custom feed (requires absolutes paths)
md nuget-feed
nuget.exe add zsv .\<path>\zsv-amd64-windows-mingw.nupkg -source <path>/nuget-feed
nuget.exe install zsv -version <version> -source <path>/nuget-feed
# Uninstall
nuget.exe delete zsv <version> -source <path>/nuget-feed
For Windows (*.nupkg
), install with choco.exe
:
# Install
choco.exe install zsv -source .\zsv-amd64-windows-mingw.nupkg
# Uninstall
choco.exe uninstall zsv
NOTE: Windows build has a runtime dependency on libwinpthread-1.dll
.
Please download it from here (https://wikidll.com/mingw-w64/libwinpthread-1-dll)
according to your Windows version and place it with zsv
executable.
See BUILD.md for more details.
Our objectives, which we were unable to find in a pre-existing project, are:
- Reasonably high performance
- Runs on any platform, including web assembly
- Available as both a library and a standalone executable / command-line interface utility (CLI)
- Memory-efficient, configurable resource limits
- Handles real-world CSV cases the same way that Excel does, including all edge
cases (quote handling, newline handling (either
\n
or\r
), embedded newlines, abnormal quoting (e.g. aaa"aaa,bbb...) - Handles other "dirty" data issues:
- Assumes valid UTF8, but does not misbehave if input contains bad UTF8
- Option to specify multi-row headers
- Does not assume or stop working in case of inconsistent numbers of columns
- Easy to use library or extend/customize CLI
There are several excellent tools that achieve high performance. Among those we considered were xsv and tsv-utils. While they met our performance objective, both were designed primarily as a utility and not a library, and were not easy enough, for our needs, to customize and/or to support modular customizations that could be maintained (or licensed) independently of the related project (in addition to the fact that they were written in Rust and D, respectively, which happen to be languages with which we lacked deep experience, especially for web assembly targeting).
Others we considered were Miller (mlr), csvkit and Go (csv module), which did not meet our performance objective. We also considered various other libraries using SIMD for CSV parsing, but none that we tried met the "real-world CSV" objective.
Hence zsv was created as a library and a versatile application, both optimized for speed and ease of development for extending and/or customizing to your needs
zsv
comes with several built-in commands:
echo
: read CSV from stdin and write it back out to stdout. This is mostly useful for demonstrating how to use the API and also how to create a plug-in, and has some limited utility beyond that e.g. for adding/removing the UTF8 BOM, or cleaning up bad UTF8select
: re-shape CSV by skipping leading garbage, combining header rows into a single header, selecting or excluding specified columns, removing duplicate columns, sampling, searching and moresql
: run ad-hoc SQL query on a CSV filedesc
: provide a quick description of your table datapretty
: format for console (fixed-width) display, or convert to markdown format2json
: convert CSV to JSON. Optionally, output in database schema2tsv
: convert CSV to TSVserialize
(inverse of flatten): convert an NxM table to a single 3x (Nx(M-1)) table with columns: Row, Column Name, Column Valueflatten
(inverse of serialize): flatten a table by combining rows that share a common value in a specified identifier columnstack
: merge CSV files verticallyjq
: run a jq filter2db
: convert from JSON to sqlite3 db
Each of these can also be built as an independent executable named zsv_xxx
where xxx
is the command name.
After installing, run zsv help
to see usage details. The typical syntax is
zsv <command> <parameters>
e.g.
zsv sql my_population_data.csv "select * from data where population > 100000"
You can extend zsv
by providing a pre-compiled shared or static library that
defines the functions specified in extension_template.h
and which zsv
loads
in one of three ways:
- as a static library that is statically linked at compile time
- as a dynamic library that is linked at compile time and located in any library search path
- as a dynamic library that is located in the same folder as the
zsv
executable and loaded at runtime if/as/when the custom mode is invoked
You can build and run a sample extension by running make test
from
app/ext_example
.
The easiest way to implement your own extension is to copy and customize the template files in app/ext_template
This release does not yet implement the full range of core features that are planned for implementation prior to beta release. If you are interested in helping, please post an issue.
- online "playground" (soon to be released)
- optimize search; add search with hyperscan or re2 regex matching, possibly parallelize?
- optional openmp or other multi-threading for row processing
- auto-generated documentation, and better documentation in general
- Additional benchmarking. Would be great to use https://bitbucket.org/ewanhiggs/csv-game/src/master/ as a springboard to benchmarking a number of various tasks
- encoding conversion e.g. UTF16 to UTF8