1 unstable release
0.1.0 | Aug 14, 2019 |
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#819 in Science
14KB
234 lines
json2csv
ALPHA
Introduction
I love using the Javascript json2csv library. It's a great tool for following the Data Science at the Command Line philosophy. I wanted to attempt a rewrite in Rust in order to improve the performance and add some features I have missed.
json2csv 0.1.0
Alex Wennerberg <alex@alexwennerberg.com>
Converts JSON into CSV
USAGE:
json2csv [FLAGS] [OPTIONS] [--] [INPUT]
FLAGS:
-F, --flatten Flatten nested jsons and arrays
-h, --help Prints help information
-V, --version Prints version information
OPTIONS:
-f, --fields <fields>... Optionally specify fields to include
-o, --output <output> Output file. If not present, writes to stdout
-U, --unwind-on <unwind-on> Unwind an array into multiple keys, similar to mongo
ARGS:
<INPUT> Input file. If not present, reads from stdin
Installation
This tool is still in alpha. Build from source:
git clone git://github.com/alexwennerberg/json2csv
cd json2csv
cargo build --release
Note that if you are using multiple tools named json2csv, you'll want to uninstall one of them or add an alias, such as json2csv-rs
Usage
For simple, flat jsons with a uniform structure, simply run json2csv input.json
If your json structure is not uniform, you may want to run json2csv input.json --get-headers
first, which will list all the headers. Then pass these headers like json2csv input.json --fields foo bar
If your json is nested, you may want to use jq to do some pre-processing. --flatten
will flatten all nested arrays in a json, such that they will have the format field.nested_field or field.nested_array.0, etc. Combine this with --get-headers
to get all nested values.
You can use the --unwind-on
option to "unwind" the json on a key. That is to say, to split a record that contains an array into an array of records containing each value of that array.
I don't include any of the formatting options that are present in the Javascript json2csv. This is following the Do One Thing and Do It Well principle -- this should just convert JSON to CSV, for any sort of reformatting or post-processing you can pipe the data into BurntSushi's excellent xsv library.
Submit a pull request for any feature requests!
Dependencies
~5–7MB
~121K SLoC