Struct vega_lite::DataFormat
source · pub struct DataFormat {
pub parse: Option<Parse>,
pub data_format_type: Option<DataFormatType>,
pub delimiter: Option<String>,
pub property: Option<String>,
pub feature: Option<String>,
pub mesh: Option<String>,
}
Expand description
An object that specifies the format for parsing the data.
Fields§
§parse: Option<Parse>
If set to "auto"
(the default), perform automatic type inference to determine the
desired data types.
If set to null
, disable type inference based on the spec and only use type inference
based on the data.
Alternatively, a parsing directive object can be provided for explicit data types. Each
property of the object corresponds to a field name, and the value to the desired data
type (one of "number"
, "boolean"
, "date"
, or null (do not parse the field)).
For example, "parse": {"modified_on": "date"}
parses the modified_on
field in each
input record a Date value.
For "date"
, we parse data based using Javascript’s
Date.parse()
.
For Specific date formats can be provided (e.g., {foo: 'date:"%m%d%Y"'}
), using the
d3-time-format syntax. UTC date
format parsing is supported similarly (e.g., {foo: 'utc:"%m%d%Y"'}
). See more about
UTC time
data_format_type: Option<DataFormatType>
Type of input data: "json"
, "csv"
, "tsv"
, "dsv"
.
The default format type is determined by the extension of the file URL.
If no extension is detected, "json"
will be used by default.
delimiter: Option<String>
The delimiter between records. The delimiter must be a single character (i.e., a single 16-bit code unit); so, ASCII delimiters are fine, but emoji delimiters are not.
property: Option<String>
The JSON property containing the desired data.
This parameter can be used when the loaded JSON file may have surrounding structure or
meta-data.
For example "property": "values.features"
is equivalent to retrieving
json.values.features
from the loaded JSON object.
feature: Option<String>
The name of the TopoJSON object set to convert to a GeoJSON feature collection.
For example, in a map of the world, there may be an object set named "countries"
.
Using the feature property, we can extract this set and generate a GeoJSON feature object
for each country.
mesh: Option<String>
The name of the TopoJSON object set to convert to mesh.
Similar to the feature
option, mesh
extracts a named TopoJSON object set.
Unlike the feature
option, the corresponding geo data is returned as a single, unified
mesh instance, not as individual GeoJSON features.
Extracting a mesh is useful for more efficiently drawing borders or other geographic
elements that you do not need to associate with specific regions such as individual
countries, states or counties.