String Functions Reference

String Functions

Name Description
BYTE_LENGTH Returns the number of BYTES in a STRING or BYTES value
CHAR_LENGTH Returns the number of unicode characters in a STRING value
STARTS_WITH Returns TRUE if a STRING begins with a given prefix
ENDS_WITH Returns TRUE if a STRING ends with a given postfix
LIKE Returns TRUE if a STRING matches a pattern
REGEX_CONTAINS Returns TRUE if a value is a partial or full match for a regular expression
REGEX_MATCH Returns TRUE if any part of a value matches a regular expression
STRING_CONCAT Concatenates multiple STRING into a STRING
STRING_CONTAINS Returns TRUE if a value contains a STRING
STRING_INDEX_OF Returns the 0-based index of the first occurrence of a STRING or BYTES value.
TO_UPPER Converts a STRING or BYTES value to uppercase.
TO_LOWER Converts a STRING or BYTES value to lowercase.
SUBSTRING Gets a substring of a STRING or BYTES value.
STRING_REVERSE Reverses a STRING or BYTES value.
STRING_REPEAT Repeats a STRING or BYTES value a specified number of times.
STRING_REPLACE_ALL Replaces all occurrences of a STRING or BYTES value.
STRING_REPLACE_ONE Replaces the first occurrence of a STRING or BYTES value.
TRIM Trims leading and trailing characters from a STRING or BYTES value.
LTRIM Trims leading characters from a STRING or BYTES value.
RTRIM Trims trailing characters from a STRING or BYTES value.
SPLIT Splits a STRING or BYTES value into an array.

BYTE_LENGTH

Syntax:

byte_length[T <: STRING | BYTES](value: T) -> INT64

Description:

Returns the number of BYTES in a STRING or BYTES value.

Examples:

value byte_length(value)
"abc" 3
"xyzabc" 6
b"abc" 3
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("title").byteLength().as("titleByteLength")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("title").byteLength().as("titleByteLength")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("title").byteLength().as("titleByteLength")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("title").byteLength().alias("titleByteLength")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("title").byteLength().alias("titleByteLength")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("title").byte_length().as_("titleByteLength"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(byteLength(field("title")).as("titleByteLength"))
        .execute()
        .get();
PipelineSnippets.java

CHAR_LENGTH

Syntax:

char_length(value: STRING) -> INT64

Description:

Returns the number of unicode code points in STRING value.

Examples:

value char_length(value)
"abc" 3
"hello" 5
"world" 5
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("title").charLength().as("titleCharLength")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("title").charLength().as("titleCharLength")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("title").charLength().as("titleCharLength")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("title").charLength().alias("titleCharLength")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("title").charLength().alias("titleCharLength")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("title").char_length().as_("titleCharLength"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(charLength(field("title")).as("titleCharLength"))
        .execute()
        .get();
PipelineSnippets.java

STARTS_WITH

Syntax:

starts_with(value: STRING, prefix: STRING) -> BOOLEAN

Description:

Returns TRUE if value begins with prefix.

Examples:

value prefix starts_with(value, prefix)
"abc" "a" true
"abc" "b" false
"abc" "" true
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("title").startsWith("The")
      .as("needsSpecialAlphabeticalSort")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("title").startsWith("The")
      .as("needsSpecialAlphabeticalSort")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("title").startsWith("The")
      .as("needsSpecialAlphabeticalSort")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("title").startsWith("The")
            .alias("needsSpecialAlphabeticalSort")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("title").startsWith("The")
            .alias("needsSpecialAlphabeticalSort")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(
        Field.of("title").starts_with("The").as_("needsSpecialAlphabeticalSort")
    )
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(startsWith(field("title"), "The").as("needsSpecialAlphabeticalSort"))
        .execute()
        .get();
PipelineSnippets.java

ENDS_WITH

Syntax:

ends_with(value: STRING, postfix: STRING) -> BOOLEAN

Description:

Returns TRUE if value ends with postfix.

Examples:

value postfix ends_with(value, postfix)
"abc" "c" true
"abc" "b" false
"abc" "" true
Node.js
const result = await db.pipeline()
  .collection("inventory/devices/laptops")
  .select(
    field("name").endsWith("16 inch")
      .as("16InLaptops")
  )
  .execute();
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("inventory/devices/laptops")
  .select([
    Field("name").endsWith("16 inch")
      .as("16InLaptops")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("inventory/devices/laptops")
    .select(
        field("name").endsWith("16 inch")
            .alias("16InLaptops")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("inventory/devices/laptops")
    .select(
        field("name").endsWith("16 inch")
            .alias("16InLaptops")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("inventory/devices/laptops")
    .select(Field.of("name").ends_with("16 inch").as_("16InLaptops"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("inventory/devices/laptops")
        .select(endsWith(field("name"), "16 inch").as("16InLaptops"))
        .execute()
        .get();
PipelineSnippets.java

LIKE

Syntax:

like(value: STRING, pattern: STRING) -> BOOLEAN

Description:

Returns TRUE if value matches pattern.

Examples:

value pattern like(value, pattern)
"Firestore" "Fire%" true
"Firestore" "%store" true
"Datastore" "Data_tore" true
"100%" "100\%" true
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("genre").like("%Fiction")
      .as("anyFiction")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("genre").like("%Fiction")
      .as("anyFiction")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("genre").like("%Fiction")
      .as("anyFiction")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("genre").like("%Fiction")
            .alias("anyFiction")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("genre").like("%Fiction")
            .alias("anyFiction")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("genre").like("%Fiction").as_("anyFiction"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(like(field("genre"), "%Fiction").as("anyFiction"))
        .execute()
        .get();
PipelineSnippets.java

REGEX_CONTAINS

Syntax:

regex_contains(value: STRING, pattern: STRING) -> BOOLEAN

Description:

Returns TRUE if some part of value matches pattern. If pattern is not a valid regular expression, this function returns an error.

Regular expressions follow the syntax of the re2 library.

Examples:

value pattern regex_contains(value, pattern)
"Firestore" "Fire" true
"Firestore" "store$" true
"Firestore" "data" false
Node.js
const result = await db.pipeline()
  .collection("documents")
  .select(
    field("title").regexContains("Firestore (Enterprise|Standard)")
      .as("isFirestoreRelated")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("documents")
  .select(
    field("title").regexContains("Firestore (Enterprise|Standard)")
      .as("isFirestoreRelated")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("documents")
  .select([
    Field("title").regexContains("Firestore (Enterprise|Standard)")
      .as("isFirestoreRelated")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("documents")
    .select(
        field("title").regexContains("Firestore (Enterprise|Standard)")
            .alias("isFirestoreRelated")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("documents")
    .select(
        field("title").regexContains("Firestore (Enterprise|Standard)")
            .alias("isFirestoreRelated")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("documents")
    .select(
        Field.of("title")
        .regex_contains("Firestore (Enterprise|Standard)")
        .as_("isFirestoreRelated")
    )
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("documents")
        .select(
            regexContains(field("title"), "Firestore (Enterprise|Standard)")
                .as("isFirestoreRelated"))
        .execute()
        .get();
PipelineSnippets.java

REGEX_MATCH

Syntax:

regex_match(value: STRING, pattern: STRING) -> BOOLEAN

Description:

Returns TRUE if value fully matches pattern. If pattern is not a valid regular expression, this function returns an error.

Regular expressions follow the syntax of the re2 library.

Examples:

value pattern regex_match(value, pattern)
"Firestore" "F.*store" true
"Firestore" "Fire" false
"Firestore" "^F.*e$" true
Node.js
const result = await db.pipeline()
  .collection("documents")
  .select(
    field("title").regexMatch("Firestore (Enterprise|Standard)")
      .as("isFirestoreExactly")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("documents")
  .select(
    field("title").regexMatch("Firestore (Enterprise|Standard)")
      .as("isFirestoreExactly")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("documents")
  .select([
    Field("title").regexMatch("Firestore (Enterprise|Standard)")
      .as("isFirestoreExactly")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("documents")
    .select(
        field("title").regexMatch("Firestore (Enterprise|Standard)")
            .alias("isFirestoreExactly")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("documents")
    .select(
        field("title").regexMatch("Firestore (Enterprise|Standard)")
            .alias("isFirestoreExactly")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("documents")
    .select(
        Field.of("title")
        .regex_match("Firestore (Enterprise|Standard)")
        .as_("isFirestoreExactly")
    )
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("documents")
        .select(
            regexMatch(field("title"), "Firestore (Enterprise|Standard)")
                .as("isFirestoreExactly"))
        .execute()
        .get();
PipelineSnippets.java

STRING_CONCAT

Syntax:

string_concat(values: STRING...) -> STRING

Description:

Concatenates two or more STRING values into a single result.

Examples:

arguments string_concat(values...)
() error
("a") "a"
("abc", "def") "abcdef"
("a", "", "c") "ac"
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("title").stringConcat(" by ", field("author"))
      .as("fullyQualifiedTitle")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("title").stringConcat(" by ", field("author"))
      .as("fullyQualifiedTitle")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("title").concat([" by ", Field("author")])
      .as("fullyQualifiedTitle")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("title").concat(" by ", field("author"))
            .alias("fullyQualifiedTitle")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("title").concat(" by ", field("author"))
            .alias("fullyQualifiedTitle")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(
        Field.of("title")
        .concat(" by ", Field.of("author"))
        .as_("fullyQualifiedTitle")
    )
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(stringConcat(field("title"), " by ", field("author")).as("fullyQualifiedTitle"))
        .execute()
        .get();
PipelineSnippets.java

STRING_CONTAINS

Syntax:

string_contains(value: STRING, substring: STRING) -> BOOLEAN

Description:

Checks if value contains the literal String substring.

Examples:

value substring string_contains(value, substring)
"abc" "b" true
"abc" "d" false
"abc" "" true
"a.c" "." true
"☃☃☃" "☃" true
Node.js
const result = await db.pipeline()
  .collection("articles")
  .select(
    field("body").stringContains("Firestore")
      .as("isFirestoreRelated")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("articles")
  .select(
    field("body").stringContains("Firestore")
      .as("isFirestoreRelated")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("articles")
  .select([
    Field("body").stringContains("Firestore")
      .as("isFirestoreRelated")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("articles")
    .select(
        field("body").stringContains("Firestore")
            .alias("isFirestoreRelated")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("articles")
    .select(
        field("body").stringContains("Firestore")
            .alias("isFirestoreRelated")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("articles")
    .select(Field.of("body").string_contains("Firestore").as_("isFirestoreRelated"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("articles")
        .select(stringContains(field("body"), "Firestore").as("isFirestoreRelated"))
        .execute()
        .get();
PipelineSnippets.java

STRING_INDEX_OF

Syntax:

string_index_of[T <: STRING | BYTES](value: T, search: T) -> INT64

Description:

Returns the 0-based index of the first occurrence of search in value.

  • Returns -1 if search is not found.
  • If value is a STRING value, the result is measured in unicode code points. If it is a BYTES value, it is measured in bytes.
  • If search is an empty STRING or BYTES value, the result is 0.

Examples:

value search string_index_of(value, search)
"hello world" "o" 4
"hello world" "l" 2
"hello world" "z" -1
"banana" "na" 2
"abc" "" 0
b"abc" b"b" 1
"é" "é" 0
b"é" b"é" 0

TO_UPPER

Syntax:

to_upper[T <: STRING | BYTES](value: T) -> T

Description:

Converts a STRING or BYTES value to uppercase.

If a byte or char does not correspond to a UTF-8 lowercase alphabetic character, it is passed through unchanged.

Examples:

value to_upper(value)
"abc" "ABC"
"AbC" "ABC"
b"abc" b"ABC"
b"a1c" b"A1C"
Node.js
const result = await db.pipeline()
  .collection("authors")
  .select(
    field("name").toUpper()
      .as("uppercaseName")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("authors")
  .select(
    field("name").toUpper()
      .as("uppercaseName")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("authors")
  .select([
    Field("name").toUpper()
      .as("uppercaseName")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("authors")
    .select(
        field("name").toUpper()
            .alias("uppercaseName")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("authors")
    .select(
        field("name").toUpper()
            .alias("uppercaseName")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("authors")
    .select(Field.of("name").to_upper().as_("uppercaseName"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("authors")
        .select(toUpper(field("name")).as("uppercaseName"))
        .execute()
        .get();
PipelineSnippets.java

TO_LOWER

Syntax:

to_lower[T <: STRING | BYTES](value: T) -> T

Description:

Converts a STRING or BYTES value to lowercase.

If a byte or char does not correspond to a UTF-8 uppercase alphabetic character, it is passed through unchanged.

Examples:

value to_lower(value)
"ABC" "abc"
"AbC" "abc"
"A1C" "a1c"
b"ABC" b"abc"
Node.js
const result = await db.pipeline()
  .collection("authors")
  .select(
    field("genre").toLower().equal("fantasy")
      .as("isFantasy")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("authors")
  .select(
    field("genre").toLower().equal("fantasy")
      .as("isFantasy")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("authors")
  .select([
    Field("genre").toLower().equal("fantasy")
      .as("isFantasy")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("authors")
    .select(
        field("genre").toLower().equal("fantasy")
            .alias("isFantasy")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("authors")
    .select(
        field("genre").toLower().equal("fantasy")
            .alias("isFantasy")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("authors")
    .select(Field.of("genre").to_lower().equal("fantasy").as_("isFantasy"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("authors")
        .select(equal(toLower(field("genre")), "fantasy").as("isFantasy"))
        .execute()
        .get();
PipelineSnippets.java

SUBSTRING

Syntax:

substring[T <: STRING | BYTES](input: T, position: INT64) -> T
substring[T <: STRING | BYTES](input: T, position: INT64, length: INT64) -> T

Description:

Returns a substring of input starting at position (zero-based index) and including up to length entries. If no length is provided, returns the substring from position to the end of the input.

  • If input is a STRING value, position and length are measured in unicode code points. If it is a BYTES value, they are measured in bytes.

  • If position is greater than the length of the input, an empty substring is returned. If position plus length is greater than the length of input, the substring is truncated to the end of input.

  • If position is negative, the position is taken from the end of the input. If the negative position is greater than the size of the input, the position is set to zero. length must be non-negative.

Examples:

When length is not provided:

input position substring(input, position)
"abc" 0 "abc"
"abc" 1 "bc"
"abc" 3 ""
"abc" -1 "c"
b"abc" 1 b"bc"

When length is provided:

input position length substring(input, position, length)
"abc" 0 1 "a"
"abc" 1 2 "bc"
"abc" -1 1 "c"
b"abc" 0 1 b"a"
Node.js
const result = await db.pipeline()
  .collection("books")
  .where(field("title").startsWith("The "))
  .select(
    field("title").substring(4)
      .as("titleWithoutLeadingThe")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .where(field("title").startsWith("The "))
  .select(
    field("title").substring(4)
      .as("titleWithoutLeadingThe")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .where(Field("title").startsWith("The "))
  .select([
    Field("title").substring(position: 4)
      .as("titleWithoutLeadingThe")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .where(field("title").startsWith("The "))
    .select(
        field("title")
          .substring(constant(4),
            field("title").charLength().subtract(4))
            .alias("titleWithoutLeadingThe")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .where(field("title").startsWith("The "))
    .select(
        field("title").substring(
          constant(4),
            field("title").charLength().subtract(4))
            .alias("titleWithoutLeadingThe")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .where(Field.of("title").starts_with("The "))
    .select(Field.of("title").substring(4).as_("titleWithoutLeadingThe"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .where(startsWith(field("title"), "The "))
        .select(
            substring(field("title"), constant(4), field("title").charLength())
                .as("titleWithoutLeadingThe"))
        .execute()
        .get();
PipelineSnippets.java

STRING_REVERSE

Syntax:

string_reverse[T <: STRING | BYTES](input: T) -> T

Description:

Returns the supplied input in reverse order.

Characters are delineated by Unicode code points when the input is a STRING, and bytes when the input is a BYTES value.

Examples:

input string_reverse(input)
"abc" "cba"
"a🌹b" "b🌹a"
"hello" "olleh"
b"abc" b"cba"
Node.js
const result = await db.pipeline()
  .collection("books")
  .select(
    field("name").reverse().as("reversedName")
  )
  .execute();
test.firestore.js

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("name").reverse().as("reversedName")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("name").reverse().as("reversedName")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("name").reverse().alias("reversedName")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("name").reverse().alias("reversedName")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("name").string_reverse().as_("reversedName"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(reverse(field("name")).as("reversedName"))
        .execute()
        .get();
PipelineSnippets.java

STRING_REPEAT

Syntax:

string_repeat[T <: STRING | BYTES](input: T, repetitions: INT64) -> T

Description:

Returns the input repeated repetitions times.

  • repetitions must be a non-negative integer.
  • If repetitions is 0, returns an empty value of the same type as input.
  • If the result exceeds the maximum allowed size (1 MB), an error is returned.

Examples:

input repetitions string_repeat(input, repetitions)
"foo" 3 "foofoofoo"
"foo" 0 ""
"a " 3 "a a a "
b"ab" 2 b"abab"
"é🦆" 2 "é🦆é🦆"

STRING_REPLACE_ALL

Syntax:

string_replace_all[T <: STRING | BYTES](input: T, find: T, replacement: T) -> T

Description:

Replaces all non-overlapping occurrences of find in input with replacement.

  • Matches are case-sensitive.
  • If find is empty, no replacements are made.

Examples:

input find replacement string_replace_all(input, find, replacement)
"foobarfoo" "foo" "baz" "bazbarbaz"
"ababab" "aba" "c" "cbab"
"foobar" "o" "" "fbar"
"é🦆🌎🦆" "🦆" "a" "éa🌎a"
b"abc" b"b" b"d" b"adc"

STRING_REPLACE_ONE

Syntax:

string_replace_one[T <: STRING | BYTES](input: T, find: T, replacement: T) -> T

Description:

Replaces the first occurrence of find in input with replacement.

  • Matches are case-sensitive.
  • If find is empty, no replacements are made.

Examples:

input find replacement string_replace_one(input, find, replacement)
"foobarfoo" "foo" "baz" "bazbarfoo"
"é" "é" "a" "a"
b"foobar" b"o" b"z" b"fzoobar"

TRIM

Syntax:

trim[T <: STRING | BYTES](input: T, values_to_trim: T) -> T
trim[T <: STRING | BYTES](input: T) -> T

Description:

Trims a specified set of BYTES or CHARS from the beginning and end of the supplied input.

  • If no values_to_trim are provided, trims whitespace characters.

Examples:

When values_to_trim is not provided:

input trim(input)
" foo " "foo"
b" foo " b"foo"
"foo" "foo"
"" ""
" " ""
"\t foo \n" "foo"
b"\t foo \n" b"foo"
"\r\f\v foo \r\f\v" "foo"
b"\r\f\v foo \r\f\v" b"foo"

When values_to_trim is provided:

input values_to_trim trim(input, values_to_trim)
"abcbfooaacb" "abc" "foo"
"abcdaabadbac" "abc" "daabad"
b"C1C2C3" b"C1" b"C2C3"
b"C1C2" "foo" error
"foo" b"C1" error

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("name").trim().as("whitespaceTrimmedName")
  )
);
test.firestore.js
Swift
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("name").trim(" \n\t").as("whitespaceTrimmedName")
  ])
  .execute()
PipelineSnippets.swift
Kotlin
Android
val result = db.pipeline()
    .collection("books")
    .select(
        field("name").trim().alias("whitespaceTrimmedName")
    )
    .execute()
DocSnippets.kt
Java
Android
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        field("name").trim().alias("whitespaceTrimmedName")
    )
    .execute();
DocSnippets.java
Python
from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("name").trim().as_("whitespaceTrimmedName"))
    .execute()
)
firestore_pipelines.py
Java
Pipeline.Snapshot result =
    firestore
        .pipeline()
        .collection("books")
        .select(trim(field("name")).as("whitespaceTrimmedName"))
        .execute()
        .get();
PipelineSnippets.java

LTRIM

Syntax:

ltrim[T <: STRING | BYTES](value: T, to_trim: T) -> T
ltrim[T <: STRING | BYTES](value: T) -> T

Description:

Trims a specified set of BYTES or CHARS from the beginning of the supplied value.

  • If to_trim is not provided, trims leading whitespace characters.

Examples:

When to_trim is not provided:

value ltrim(value)
" foo " "foo "
"foo" "foo"

When to_trim is provided:

value to_trim ltrim(value, to_trim)
"aaabc" "a" "bc"
"abacaba" "ba" "caba"
"é" "é" ""

RTRIM

Syntax:

rtrim[T <: STRING | BYTES](value: T, to_trim: T) -> T
rtrim[T <: STRING | BYTES](value: T) -> T

Description:

Trims a specified set of BYTES or CHARS from the end of the supplied value.

  • If to_trim is not provided, trims trailing whitespace characters.

Examples:

When to_trim is not provided:

value rtrim(value)
" foo " " foo"
"foo" "foo"

When to_trim is provided:

value to_trim rtrim(value, to_trim)
"abccc" "c" "ab"
"abacaba" "ba" "abac"
"é" "é" ""

SPLIT

Syntax:

split(input: STRING) -> ARRAY<STRING>
split[T <: STRING | BYTES](input: T, delimiter: T) -> ARRAY<T>

Description:

Splits a STRING or BYTES value, using a delimiter.

  • For STRING the default delimiter is the comma ,. The delimiter is treated as a single string.

  • For BYTES, you must specify a delimiter.

  • Splitting on an empty delimiter produces an array of Unicode codepoints for STRING values, and an array of BYTES for BYTES values.

  • Splitting an empty STRING returns an ARRAY with a single empty STRING.

Examples:

When delimiter is not provided:

input split(input)
"foo,bar,foo" ["foo", "bar", "foo"]
"foo" ["foo"]
",foo," ["", "foo", ""]
"" [""]
b"C120C2C4" error

When delimiter is provided:

input delimiter split(input, delimiter)
"foo bar foo" " " ["foo", "bar", "foo"]
"foo bar foo" "z" ["foo bar foo"]
"abc" "" ["a", "b", "c"]
b"C1,C2,C4" b"," [b"C1", b"C2", b"C4"]
b"ABC" b"" [b"A", b"B", b"C"]
"foo" b"C1" error

What's next