ASCII folding token filteredit
Converts alphabetic, numeric, and symbolic characters that are not in the Basic
Latin Unicode block (first 127 ASCII characters) to their ASCII equivalent, if
one exists. For example, the filter changes à to a.
This filter uses Lucene’s ASCIIFoldingFilter.
Exampleedit
The following analyze API request uses the asciifolding
filter to drop the diacritical marks in açaí à la carte:
GET /_analyze
{
"tokenizer" : "standard",
"filter" : ["asciifolding"],
"text" : "açaí à la carte"
}
The filter produces the following tokens:
[ acai, a, la, carte ]
Add to an analyzeredit
The following create index API request uses the
asciifolding filter to configure a new
custom analyzer.
PUT /asciifold_example
{
"settings" : {
"analysis" : {
"analyzer" : {
"standard_asciifolding" : {
"tokenizer" : "standard",
"filter" : ["asciifolding"]
}
}
}
}
}
Configurable parametersedit
-
preserve_original -
(Optional, boolean)
If
true, emit both original tokens and folded tokens. Defaults tofalse.
Customizeedit
To customize the asciifolding filter, duplicate it to create the basis
for a new custom token filter. You can modify the filter using its configurable
parameters.
For example, the following request creates a custom asciifolding filter with
preserve_original set to true:
PUT /asciifold_example
{
"settings" : {
"analysis" : {
"analyzer" : {
"standard_asciifolding" : {
"tokenizer" : "standard",
"filter" : ["my_ascii_folding"]
}
},
"filter" : {
"my_ascii_folding" : {
"type" : "asciifolding",
"preserve_original" : true
}
}
}
}
}