模式替换字符过滤器
编辑模式替换字符过滤器编辑
pattern_replace 字符过滤器使用正则表达式来匹配应该被替换为指定替换字符串的字符。替换字符串可以引用正则表达式中的捕获组。
注意病态正则表达式
模式替换字符过滤器使用 Java 正则表达式.
编写不当的正则表达式可能会运行非常缓慢，甚至抛出 StackOverflowError 并导致运行它的节点突然退出。
阅读更多关于 病态正则表达式以及如何避免它们的信息。
配置编辑
pattern_replace 字符过滤器接受以下参数
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一个 Java 正则表达式。必需。 |
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替换字符串，可以使用 |
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Java 正则表达式 标志。标志应该用管道分隔，例如 |
示例配置编辑
在这个例子中，我们配置 pattern_replace 字符过滤器将数字中的任何嵌入式连字符替换为下划线，即 123-456-789 → 123_456_789
response = client.indices.create(
index: 'my-index-000001',
body: {
settings: {
analysis: {
analyzer: {
my_analyzer: {
tokenizer: 'standard',
char_filter: [
'my_char_filter'
]
}
},
char_filter: {
my_char_filter: {
type: 'pattern_replace',
pattern: '(\\d+)-(?=\\d)',
replacement: '$1_'
}
}
}
}
}
)
puts response
response = client.indices.analyze(
index: 'my-index-000001',
body: {
analyzer: 'my_analyzer',
text: 'My credit card is 123-456-789'
}
)
puts response
PUT my-index-000001
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "standard",
"char_filter": [
"my_char_filter"
]
}
},
"char_filter": {
"my_char_filter": {
"type": "pattern_replace",
"pattern": "(\\d+)-(?=\\d)",
"replacement": "$1_"
}
}
}
}
}
POST my-index-000001/_analyze
{
"analyzer": "my_analyzer",
"text": "My credit card is 123-456-789"
}
上面的例子产生了以下术语
[ My, credit, card, is, 123_456_789 ]
使用改变原始文本长度的替换字符串将适用于搜索目的，但会导致不正确的突出显示，如以下示例所示。
这个例子在遇到小写字母后跟大写字母时插入一个空格（即 fooBarBaz → foo Bar Baz），允许单独查询 camelCase 单词
response = client.indices.create(
index: 'my-index-000001',
body: {
settings: {
analysis: {
analyzer: {
my_analyzer: {
tokenizer: 'standard',
char_filter: [
'my_char_filter'
],
filter: [
'lowercase'
]
}
},
char_filter: {
my_char_filter: {
type: 'pattern_replace',
pattern: '(?<=\\p{Lower})(?=\\p{Upper})',
replacement: ' '
}
}
}
},
mappings: {
properties: {
text: {
type: 'text',
analyzer: 'my_analyzer'
}
}
}
}
)
puts response
response = client.indices.analyze(
index: 'my-index-000001',
body: {
analyzer: 'my_analyzer',
text: 'The fooBarBaz method'
}
)
puts response
PUT my-index-000001
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "standard",
"char_filter": [
"my_char_filter"
],
"filter": [
"lowercase"
]
}
},
"char_filter": {
"my_char_filter": {
"type": "pattern_replace",
"pattern": "(?<=\\p{Lower})(?=\\p{Upper})",
"replacement": " "
}
}
}
},
"mappings": {
"properties": {
"text": {
"type": "text",
"analyzer": "my_analyzer"
}
}
}
}
POST my-index-000001/_analyze
{
"analyzer": "my_analyzer",
"text": "The fooBarBaz method"
}
上面返回以下术语
[ the, foo, bar, baz, method ]
查询 bar 将正确找到文档，但结果的突出显示将产生不正确的突出显示，因为我们的字符过滤器改变了原始文本的长度
response = client.index(
index: 'my-index-000001',
id: 1,
refresh: true,
body: {
text: 'The fooBarBaz method'
}
)
puts response
response = client.search(
index: 'my-index-000001',
body: {
query: {
match: {
text: 'bar'
}
},
highlight: {
fields: {
text: {}
}
}
}
)
puts response
PUT my-index-000001/_doc/1?refresh
{
"text": "The fooBarBaz method"
}
GET my-index-000001/_search
{
"query": {
"match": {
"text": "bar"
}
},
"highlight": {
"fields": {
"text": {}
}
}
}
上面的输出是
{
"timed_out": false,
"took": $body.took,
"_shards": {
"total": 1,
"successful": 1,
"skipped" : 0,
"failed": 0
},
"hits": {
"total" : {
"value": 1,
"relation": "eq"
},
"max_score": 0.2876821,
"hits": [
{
"_index": "my-index-000001",
"_id": "1",
"_score": 0.2876821,
"_source": {
"text": "The fooBarBaz method"
},
"highlight": {
"text": [
"The foo<em>Ba</em>rBaz method"
]
}
}
]
}
}