add pattern replace token filter docs #8241

_analyzers/token-filters/index.md

@@ -44,7 +44,7 @@ Token filter | Underlying Lucene token filter|  Description
 `ngram` | [NGramTokenFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ngram/NGramTokenFilter.html) | Tokenizes the given token into n-grams of lengths between `min_gram` and `max_gram`.
 Normalization | `arabic_normalization`: [ArabicNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ar/ArabicNormalizer.html) <br> `german_normalization`: [GermanNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/de/GermanNormalizationFilter.html) <br> `hindi_normalization`: [HindiNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/hi/HindiNormalizer.html) <br> `indic_normalization`: [IndicNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/in/IndicNormalizer.html) <br> `sorani_normalization`: [SoraniNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ckb/SoraniNormalizer.html) <br> `persian_normalization`: [PersianNormalizer](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/fa/PersianNormalizer.html) <br> `scandinavian_normalization` : [ScandinavianNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/ScandinavianNormalizationFilter.html) <br> `scandinavian_folding`: [ScandinavianFoldingFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/ScandinavianFoldingFilter.html) <br> `serbian_normalization`: [SerbianNormalizationFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/sr/SerbianNormalizationFilter.html) | Normalizes the characters of one of the listed languages.
 `pattern_capture` | N/A | Generates a token for every capture group in the provided regular expression. Uses [Java regular expression syntax](https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html).
-`pattern_replace` | N/A | Matches a pattern in the provided regular expression and replaces matching substrings. Uses [Java regular expression syntax](https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html).
+[`pattern_replace`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/pattern-replace/) | N/A | Matches a pattern in the provided regular expression and replaces matching substrings. Uses [Java regular expression syntax](https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html).
 `phonetic` | N/A | Uses a phonetic encoder to emit a metaphone token for each token in the token stream. Requires installing the `analysis-phonetic` plugin.
 `porter_stem` | [PorterStemFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/en/PorterStemFilter.html) | Uses the [Porter stemming algorithm](https://tartarus.org/martin/PorterStemmer/) to perform algorithmic stemming for the English language.
 `predicate_token_filter` | N/A | Removes tokens that don’t match the specified predicate script. Supports inline Painless scripts only.

_analyzers/token-filters/pattern-replace.md

@@ -0,0 +1,116 @@
+---
+layout: default
+title: Pattern replace
+parent: Token filters
+nav_order: 320
+---
+
+# Pattern replace token filter
+
+The `pattern_replace` token filter allows you to modify tokens using regular expressions. This filter replaces patterns in tokens with the specified values, giving you flexibility in transforming or normalizing tokens before indexing them. It's particularly useful when you need to clean or standardize text during analysis.
+
+## Parameters
+
+The `pattern_replace` token filter can be configured with the following parameters.
+
+Parameter | Required/Optional | Data type | Description
+:--- | :--- | :--- | :--- 
+`pattern` | Required | String | A regular expression pattern that matches the text which needs to be replaced.
+`all` | Optional | Boolean | Whether to replace all pattern matches. If `false`, only the first match is replaced. Default is `true`.
+`replacement` | Optional | String | A string with which to replace the matched pattern. Default is an empty string.
+
+
+## Example
+
+The following example request creates a new index named `text_index` and configures an analyzer with a `pattern_replace` filter to replace tokens containing digits with the string `[NUM]`:
+
+```json
+PUT /text_index
+{
+  "settings": {
+    "analysis": {
+      "filter": {
+        "number_replace_filter": {
+          "type": "pattern_replace",
+          "pattern": "\\d+",
+          "replacement": "[NUM]"
+        }
+      },
+      "analyzer": {
+        "number_analyzer": {
+          "tokenizer": "standard",
+          "filter": [
+            "lowercase",
+            "number_replace_filter"
+          ]
+        }
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Generated tokens
+
+Use the following request to examine the tokens generated using the analyzer:
+
+```json
+POST /text_index/_analyze
+{
+  "text": "Visit us at 98765 Example St.",
+  "analyzer": "number_analyzer"
+}
+```
+{% include copy-curl.html %}
+
+The response contains the generated tokens:
+
+```json
+{
+  "tokens": [
+    {
+      "token": "visit",
+      "start_offset": 0,
+      "end_offset": 5,
+      "type": "<ALPHANUM>",
+      "position": 0
+    },
+    {
+      "token": "us",
+      "start_offset": 6,
+      "end_offset": 8,
+      "type": "<ALPHANUM>",
+      "position": 1
+    },
+    {
+      "token": "at",
+      "start_offset": 9,
+      "end_offset": 11,
+      "type": "<ALPHANUM>",
+      "position": 2
+    },
+    {
+      "token": "[NUM]",
+      "start_offset": 12,
+      "end_offset": 17,
+      "type": "<NUM>",
+      "position": 3
+    },
+    {
+      "token": "example",
+      "start_offset": 18,
+      "end_offset": 25,
+      "type": "<ALPHANUM>",
+      "position": 4
+    },
+    {
+      "token": "st",
+      "start_offset": 26,
+      "end_offset": 28,
+      "type": "<ALPHANUM>",
+      "position": 5
+    }
+  ]
+}
+```