Merge pull request #276 from influxdata/flux/regexp-functions

Flux regular expression functions

content/v2.0/reference/flux/functions/regexp/_index.md

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+---
+title: Flux regular expressions package
+list_title: Regular expressions package
+description: >
+  The Flux regular expressions package includes functions that provide enhanced
+  regular expression functionality. Import the `regexp` package.
+menu:
+  v2_0_ref:
+    name: Regular expressions
+    parent: Flux packages and functions
+weight: 205
+v2.0/tags: [regex, functions]
+---
+
+The Flux regular expressions package includes functions that provide enhanced
+regular expression functionality. Import the `regexp` package.
+
+```js
+import "regexp"
+```
+
+{{< children type="functions" show="pages" >}}

content/v2.0/reference/flux/functions/regexp/compile.md

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+---
+title: regexp.compile() function
+description: >
+  The `regexp.compile()` function parses a regular expression and, if successful,
+  returns a Regexp object that can be used to match against text.
+menu:
+  v2_0_ref:
+    name: regexp.compile
+    parent: Regular expressions
+weight: 301
+---
+
+The `regexp.compile()` function parses a regular expression and, if successful,
+returns a Regexp object that can be used to match against text.
+
+_**Output data type:** Regexp_
+
+```js
+import "regexp"
+
+regexp.compile(v: "abcd")
+
+// Returns the regexp object `abcd`
+```
+
+## Parameters
+
+### v
+The string value to parse into a regular expression.
+
+_**Data type:** String_
+
+## Examples
+
+###### Use a string value as a regular expression
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      regexStr: r.regexStr,
+      _value: r._value,
+      firstRegexMatch: findString(
+        r: regexp.compile(v: regexStr),
+        v: r._value
+      )
+    })
+  )
+```

content/v2.0/reference/flux/functions/regexp/findstring.md

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+---
+title: regexp.findString() function
+description: The `regexp.findString()` function returns the left-most regular expression match in a string.
+menu:
+  v2_0_ref:
+    name: regexp.findString
+    parent: Regular expressions
+weight: 301
+related:
+  - /v2.0/reference/flux/functions/regexp/splitregexp
+---
+
+The `regexp.findString()` function returns the left-most regular expression match in a string.
+
+_**Output data type:** String_
+
+```js
+import "regexp"
+
+findString(r: /foo.?/, v: "seafood fool")
+
+// Returns "food"
+```
+
+## Parameters
+
+### r
+The regular expression used to search `v`.
+
+_**Data type:** Regexp_
+
+### v
+The string value to search.
+
+_**Data type:** String_
+
+## Examples
+
+###### Find the first regular expression match in each row
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      message: r.message,
+      regexp: r.regexp,
+      match: regexp.findString(r: r.regexp, v: r.message)
+    })
+  )
+```

content/v2.0/reference/flux/functions/regexp/findstringindex.md

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+---
+title: regexp.findStringIndex() function
+description: >
+  The `regexp.findStringIndex()` function returns a two-element array of integers defining
+  the beginning and ending indexes of the left-most regular expression match in a string.
+menu:
+  v2_0_ref:
+    name: regexp.findStringIndex
+    parent: Regular expressions
+weight: 301
+related:
+  - /v2.0/reference/flux/functions/regexp/compile
+---
+
+The `regexp.findStringIndex()` function returns a two-element array of integers defining
+the beginning and ending indexes of the left-most regular expression match in a string.
+
+_**Output data type:** Array of Integers_
+
+```js
+import "regexp"
+
+regexp.findStringIndex(r: /ab?/, v: "tablet")
+
+// Returns [1, 3]
+```
+
+## Parameters
+
+### r
+The regular expression used to search `v`.
+
+_**Data type:** Regexp_
+
+### v
+The string value to search.
+
+_**Data type:** String_
+
+## Examples
+
+###### Index the bounds of first regular expression match in each row
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      regexStr: r.regexStr,
+      _value: r._value,
+      matchIndex: regexp.findStringIndex(
+        r: regexp.compile(r.regexStr),
+        v: r._value
+      )
+    })
+  )
+```

content/v2.0/reference/flux/functions/regexp/getstring.md

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+---
+title: regexp.getString() function
+description: The `regexp.getString()` function returns the source string used to compile a regular expression.
+menu:
+  v2_0_ref:
+    name: regexp.getString
+    parent: Regular expressions
+weight: 301
+related:
+  - /v2.0/reference/flux/functions/regexp/compile
+---
+
+The `regexp.getString()` function returns the source string used to compile a regular expression.
+
+_**Output data type:** String_
+
+```js
+import "regexp"
+
+regexp.getString(r: /[a-zA-Z]/)
+
+// Returns "[a-zA-Z]"
+```
+
+## Parameters
+
+### r
+The regular expression object to convert to a string.
+
+_**Data type:** Regexp_
+
+## Examples
+
+###### Convert regular expressions into strings in each row
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      regex: r.regex,
+      regexStr: regexp.getString(r: r.regex)
+    })
+  )
+```

content/v2.0/reference/flux/functions/regexp/matchregexpstring.md

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+---
+title: regexp.matchRegexpString() function
+description: >
+  The `regexp.matchRegexpString()` function tests if a string contains any match
+  to a regular expression.
+menu:
+  v2_0_ref:
+    name: regexp.matchRegexpString
+    parent: Regular expressions
+weight: 301
+---
+
+The `regexp.matchRegexpString()` function tests if a string contains any match
+to a regular expression.
+
+_**Output data type:** Boolean_
+
+```js
+import "regexp"
+
+regexp.matchRegexpString(r: /(gopher){2}/, v: "gophergophergopher")
+
+// Returns true
+```
+
+## Parameters
+
+### r
+The regular expression used to search `v`.
+
+_**Data type:** Regexp_
+
+### v
+The string value to search.
+
+_**Data type:** String_
+
+## Examples
+
+###### Filter by columns that contain matches to a regular expression
+```js
+import "regexp"
+
+data
+  |> filter(fn: (r) =>
+    regexp.matchRegexpString(
+      r: /Alert\:/,
+      v: r.message
+    )
+  )
+```

content/v2.0/reference/flux/functions/regexp/quotemeta.md

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+---
+title: regexp.quoteMeta() function
+description: >
+  The `regexp.quoteMeta()` function escapes all regular expression metacharacters inside of a string.
+menu:
+  v2_0_ref:
+    name: regexp.quoteMeta
+    parent: Regular expressions
+weight: 301
+---
+
+The `regexp.quoteMeta()` function escapes all regular expression metacharacters inside of a string.
+
+_**Output data type:** String_
+
+```js
+import "regexp"
+
+regexp.quoteMeta(v: ".+*?()|[]{}^$")
+
+// Returns "\.\+\*\?\(\)\|\[\]\{\}\^\$"
+```
+
+## Parameters
+
+### v
+The string that contains regular expression metacharacters to escape.
+
+_**Data type:** String_
+
+## Examples
+
+###### Escape regular expression meta characters in column values
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      notes: r.notes,
+      notes_escaped: regexp.quoteMeta(v: r.notes)
+    })
+  )
+```

content/v2.0/reference/flux/functions/regexp/replaceallstring.md

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+---
+title: regexp.replaceAllString() function
+description: >
+  The `regexp.replaceAllString()` function replaces all regular expression matches
+  in a string with a specified replacement.
+menu:
+  v2_0_ref:
+    name: regexp.replaceAllString
+    parent: Regular expressions
+weight: 301
+---
+
+The `regexp.replaceAllString()` function replaces all regular expression matches
+in a string with a specified replacement.
+
+_**Output data type:** String_
+
+```js
+import "regexp"
+
+regexp.replaceAllString(r: /a(x*)b/, v: "-ab-axxb-", t: "T")
+
+// Returns "-T-T-"
+```
+
+## Parameters
+
+### r
+The regular expression used to search `v`.
+
+_**Data type:** Regexp_
+
+### v
+The string value to search.
+
+_**Data type:** String_
+
+### t
+The replacement for matches to `r`.
+
+_**Data type:** String_
+
+## Examples
+
+###### Replace regular expression matches in string column values
+```js
+import "regexp"
+
+data
+  |> map(fn: (r) => ({
+      r with
+      message: r.message,
+      updated_message: regexp.replaceAllString(
+        r: /cat|bird|ferret/,
+        v: r.message,
+        t: "dog"
+      )
+  }))
+```

content/v2.0/reference/flux/functions/regexp/splitregexp.md

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+---
+title: regexp.splitRegexp() function
+description: >
+  The `regexp.splitRegexp()` function splits a string into substrings separated by
+  regular expression matches and returns an array of `i` substrings between matches.
+menu:
+  v2_0_ref:
+    name: regexp.splitRegexp
+    parent: Regular expressions
+weight: 301
+---
+
+The `regexp.splitRegexp()` function splits a string into substrings separated by
+regular expression matches and returns an array of `i` substrings between matches.
+
+_**Output data type:** Array of Strings_
+
+```js
+import "regexp"
+
+regexp.splitRegexp(r: /a*/, v: "abaabaccadaaae", i: 5)
+
+// Returns ["", "b", "b", "c", "cadaaae"]
+```
+
+## Parameters
+
+### r
+The regular expression used to search `v`.
+
+_**Data type:** Regexp_
+
+### v
+The string value to search.
+
+_**Data type:** String_
+
+### i
+The number of substrings to return.
+
+_**Data type:** Integer_