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The Enhanced Character Separated Values format was developed within the Astropy project and is described in Astropy APE6 (DOI). It is composed of a YAML header followed by a CSV-like body, and is intended to be a human-readable and maybe even human-writable format with rich metadata. Most of the useful per-column and per-table metadata is preserved when de/serializing to this format. The version supported by this writer is currently ECSV 1.0.

ECSV allows either a space or a comma for delimiting values, controlled by the delimiter configuration option. If ecsv(delimiter=comma) is used, then removing the YAML header will leave a CSV file that can be interpreted by the CSV inputhandler or imported into other CSV-capable applications.

Following the ECSV 1.0 specification, array-valued columns are supported. ECSV 1.0, required for working with array-valued columns, is supported by Astropy v4.3 and later.

The handler behaviour may be modified by specifying one or more comma-separated name=value configuration options in parentheses after the handler name, e.g. "ecsv(delimiter=comma)". The following options are available:

delimiter = comma|space
Delimiter character, which for ECSV may be either a space or a comma. Permitted values are "space" or "comma".

If no output format is explicitly chosen, writing to a filename with the extension ".ecsv" (case insensitive) will select ECSV format for output.

An example looks like this:

# %ECSV 1.0
# ---
# datatype:
# -
#   name: RECNO
#   datatype: int32
# -
#   name: SPECIES
#   datatype: string
# -
#   name: NAME
#   datatype: string
#   description: How one should address the animal in public & private.
# -
#   name: LEGS
#   datatype: int32
#   meta:
#     utype: anatomy:limb
# -
#   name: HEIGHT
#   datatype: float64
#   unit: m
#   meta:
#     VOTable precision: 2
# -
#   name: MAMMAL
#   datatype: bool
# meta:
#   name: animals.vot
#   Description: Some animals
#   Author: Mark Taylor
1 pig "Pigling Bland" 4 0.8 True
2 cow Daisy 4 2.0 True
3 goldfish Dobbin "" 0.05 False
4 ant "" 6 0.001 False
5 ant "" 6 0.001 False
6 "queen ant" Ma'am 6 0.002 False
7 human Mark 2 1.8 True

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