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Funzioni aritmetiche

Tutte le funzioni aritmetiche in Cloud Firestore hanno i seguenti comportamenti:

Restituisce NULL se uno dei parametri di input è NULL.
Restituisce NaN se uno degli argomenti è NaN.
Genera un errore se si verifica un overflow o un underflow.

Inoltre, quando una funzione aritmetica accetta più argomenti numerici di tipi diversi (ad esempio: add(5.0, 6)), Cloud Firestore converte implicitamente gli argomenti nel tipo di input più ampio. Se vengono forniti solo input INT32, il tipo di reso sarà INT64.

Nome	Descrizione
`ABS`	Restituisce il valore assoluto di un `number`
`ADD`	Restituisce il valore di `x + y`
`SUBTRACT`	Restituisce il valore di `x - y`
`MULTIPLY`	Restituisce il valore di `x * y`
`DIVIDE`	Restituisce il valore di `x / y`
`MOD`	Restituisce il resto della divisione di `x / y`
`CEIL`	Restituisce il numero intero più piccolo maggiore o uguale a `number`.
`FLOOR`	Restituisce la parte intera di un `number`
`ROUND`	Arrotonda un `number` a `places` cifre decimali
`POW`	Restituisce il valore di `base^exponent`
`SQRT`	Restituisce la radice quadrata di un `number`
`EXP`	Restituisce il numero di Eulero elevato alla potenza di `exponent`
`LN`	Restituisce il logaritmo naturale di un `number`
`LOG`	Restituisce il logaritmo di un `number`
`LOG10`	Restituisce il logaritmo di un `number` in base `10`
`RAND`	Restituisce un numero pseudo-casuale con rappresentazione in virgola mobile

ABS

Sintassi:

abs[N <: INT32 | INT64 | FLOAT64](number: N) -> N

Descrizione:

Restituisce il valore assoluto di un number.

Genera un errore quando la funzione causerebbe l'overflow di un valore INT32 o INT64.

Esempi:

numero	`abs(number)`
10	10
-10	10
10L	10L
-0.0	0.0
10.5	10.5
-10,5	10.5
-2³¹	`[error]`
-2⁶³	`[error]`

AGGIUNGI

Sintassi:

add[N <: INT32 | INT64 | FLOAT64](x: N, y: N) -> N

Descrizione:

Restituisce il valore di x + y.

Esempi:

x	y	`add(x, y)`
20	3	23
10,0	1	11.0
22,5	2.0	24,5
INT64.MAX	1	`[error]`
INT64.MIN	-1	`[error]`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("soldBooks").add(field("unsoldBooks")).as("totalBooks"))
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("soldBooks").add(Field("unsoldBooks")).as("totalBooks")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(Expression.add(field("soldBooks"), field("unsoldBooks")).alias("totalBooks"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.add(field("soldBooks"), field("unsoldBooks")).alias("totalBooks"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("soldBooks").add(Field.of("unsoldBooks")).as_("totalBooks"))
    .execute()
)firestore_pipelines.py

SUBTRACT

Sintassi:

subtract[N <: INT32 | INT64 | FLOAT64](x: N, y: N) -> N

Descrizione:

Restituisce il valore di x - y.

Esempi:

x	y	`subtract(x, y)`
20	3	17
10,0	1	9.0
22,5	2.0	20,5
INT64.MAX	-1	`[error]`
INT64.MIN	1	`[error]`

Web

const storeCredit = 7;
const result = await execute(db.pipeline()
  .collection("books")
  .select(field("price").subtract(constant(storeCredit)).as("totalCost"))
);test.firestore.js

Swift

let storeCredit = 7
let result = try await db.pipeline()
  .collection("books")
  .select([Field("price").subtract(Constant(storeCredit)).as("totalCost")])
  .execute()PipelineSnippets.swift

Kotlin

val storeCredit = 7
val result = db.pipeline()
    .collection("books")
    .select(Expression.subtract(field("price"), storeCredit).alias("totalCost"))
    .execute()DocSnippets.kt

Java

int storeCredit = 7;
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.subtract(field("price"), storeCredit).alias("totalCost"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

store_credit = 7
result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("price").subtract(store_credit).as_("totalCost"))
    .execute()
)firestore_pipelines.py

MULTIPLY

Sintassi:

multiply[N <: INT32 | INT64 | FLOAT64](x: N, y: N) -> N

Descrizione:

Restituisce il valore di x * y.

Esempi:

x	y	`multiply(x, y)`
20	3	60
10,0	1	10,0
22,5	2.0	45,0
INT64.MAX	2	`[error]`
INT64.MIN	2	`[error]`
FLOAT64.MAX	FLOAT64.MAX	`+inf`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("price").multiply(field("soldBooks")).as("revenue"))
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("price").multiply(Field("soldBooks")).as("revenue")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(Expression.multiply(field("price"), field("soldBooks")).alias("revenue"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.multiply(field("price"), field("soldBooks")).alias("revenue"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("price").multiply(Field.of("soldBooks")).as_("revenue"))
    .execute()
)firestore_pipelines.py

DIVIDE

Sintassi:

divide[N <: INT32 | INT64 | FLOAT64](x: N, y: N) -> N

Descrizione:

Restituisce il valore di x / y. La divisione intera viene troncata.

Esempi:

x	y	`divide(x, y)`
20	3	6
10,0	3	3,333…
22,5	2	11.25
10	0	`[error]`
1.0	0.0	`+inf`
-1.0	0.0	`-inf`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("ratings").divide(field("soldBooks")).as("reviewRate"))
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("ratings").divide(Field("soldBooks")).as("reviewRate")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(Expression.divide(field("ratings"), field("soldBooks")).alias("reviewRate"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.divide(field("ratings"), field("soldBooks")).alias("reviewRate"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("ratings").divide(Field.of("soldBooks")).as_("reviewRate"))
    .execute()
)firestore_pipelines.py

MOD

Sintassi:

mod[N <: INT32 | INT64 | FLOAT64](x: N, y: N) -> N

Descrizione:

Restituisce il resto di x / y.

Genera un error quando y è zero per i tipi interi (INT64).
Restituisce NaN quando y è zero per i tipi float (FLOAT64).

Esempi:

x	y	`mod(x, y)`
20	3	2
-10	3	-1
10	-3	1
-10	-3	-1
10	1	0
22,5	2	0,5
22,5	0.0	`NaN`
25	0	`[error]`

Web

const displayCapacity = 1000;
const result = await execute(db.pipeline()
  .collection("books")
  .select(field("unsoldBooks").mod(constant(displayCapacity)).as("warehousedBooks"))
);test.firestore.js

Swift

let displayCapacity = 1000
let result = try await db.pipeline()
  .collection("books")
  .select([Field("unsoldBooks").mod(Constant(displayCapacity)).as("warehousedBooks")])
  .execute()PipelineSnippets.swift

Kotlin

val displayCapacity = 1000
val result = db.pipeline()
    .collection("books")
    .select(Expression.mod(field("unsoldBooks"), displayCapacity).alias("warehousedBooks"))
    .execute()DocSnippets.kt

Java

int displayCapacity = 1000;
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.mod(field("unsoldBooks"), displayCapacity).alias("warehousedBooks"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

display_capacity = 1000
result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("unsoldBooks").mod(display_capacity).as_("warehousedBooks"))
    .execute()
)firestore_pipelines.py

CEIL

Sintassi:

ceil[N <: INT32 | INT64 | FLOAT64](number: N) -> N

Descrizione:

Restituisce il valore intero più piccolo che non sia inferiore a number.

Esempi:

numero	`ceil(number)`
20	20
10	10
0	0
24L	24L
-0.4	-0.0
0,4	1.0
22,5	23,0
`+inf`	`+inf`
`-inf`	`-inf`

Web

const booksPerShelf = 100;
const result = await execute(db.pipeline()
  .collection("books")
  .select(
    field("unsoldBooks").divide(constant(booksPerShelf)).ceil().as("requiredShelves")
  )
);test.firestore.js

Swift

let booksPerShelf = 100
let result = try await db.pipeline()
  .collection("books")
  .select([
    Field("unsoldBooks").divide(Constant(booksPerShelf)).ceil().as("requiredShelves")
  ])
  .execute()PipelineSnippets.swift

Kotlin

val booksPerShelf = 100
val result = db.pipeline()
    .collection("books")
    .select(
        Expression.divide(field("unsoldBooks"), booksPerShelf).ceil().alias("requiredShelves")
    )
    .execute()DocSnippets.kt

Java

int booksPerShelf = 100;
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(
        Expression.divide(field("unsoldBooks"), booksPerShelf).ceil().alias("requiredShelves")
    )
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

books_per_shelf = 100
result = (
    client.pipeline()
    .collection("books")
    .select(
        Field.of("unsoldBooks")
        .divide(books_per_shelf)
        .ceil()
        .as_("requiredShelves")
    )
    .execute()
)firestore_pipelines.py

FLOOR

Sintassi:

floor[N <: INT32 | INT64 | FLOAT64](number: N) -> N

Descrizione:

Restituisce il valore intero più grande non superiore a number.

Esempi:

numero	`floor(number)`
20	20
10	10
0	0
2147483648	2147483648
-0.4	-1.0
0,4	0.0
22,5	22,0
`+inf`	`+inf`
`-inf`	`-inf`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .addFields(
    field("wordCount").divide(field("pages")).floor().as("wordsPerPage")
  )
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .addFields([
    Field("wordCount").divide(Field("pages")).floor().as("wordsPerPage")
  ])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .addFields(
        Expression.divide(field("wordCount"), field("pages")).floor().alias("wordsPerPage")
    )
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .addFields(
        Expression.divide(field("wordCount"), field("pages")).floor().alias("wordsPerPage")
    )
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .add_fields(
        Field.of("wordCount").divide(Field.of("pages")).floor().as_("wordsPerPage")
    )
    .execute()
)firestore_pipelines.py

ROUND

Sintassi:

round[N <: INT32 | INT64 | FLOAT64 | DECIMAL128](number: N) -> N
round[N <: INT32 | INT64 | FLOAT64 | DECIMAL128](number: N, places: INT64) -> N

Descrizione:

Arrotonda places cifre di un number. Arrotonda le cifre a destra del separatore decimale se places è positivo e a sinistra del separatore decimale se è negativo.

Se viene fornito solo number, il valore viene arrotondato al numero intero più vicino.
Arrotonda lontano da zero nei casi a metà.
Viene generato un error se l'arrotondamento con un valore places negativo comporta un overflow.

Esempi:

numero	luoghi	`round(number, places)`
15.5	0	16.0
-15,5	0	-16.0
15	1	15
15	0	15
15	-1	20
15	-2	0
15,48924	1	15.5
2³¹-1	-1	`[error]`
2⁶³-1L	-1	`[error]`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("soldBooks").multiply(field("price")).round().as("partialRevenue"))
  .aggregate(field("partialRevenue").sum().as("totalRevenue"))
  );test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("soldBooks").multiply(Field("price")).round().as("partialRevenue")])
  .aggregate([Field("partialRevenue").sum().as("totalRevenue")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(Expression.multiply(field("soldBooks"), field("price")).round().alias("partialRevenue"))
    .aggregate(AggregateFunction.sum("partialRevenue").alias("totalRevenue"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(Expression.multiply(field("soldBooks"), field("price")).round().alias("partialRevenue"))
    .aggregate(AggregateFunction.sum("partialRevenue").alias("totalRevenue"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(
        Field.of("soldBooks")
        .multiply(Field.of("price"))
        .round()
        .as_("partialRevenue")
    )
    .aggregate(Field.of("partialRevenue").sum().as_("totalRevenue"))
    .execute()
)firestore_pipelines.py

POW

Sintassi:

pow(base: FLOAT64, exponent: FLOAT64) -> FLOAT64

Descrizione:

Restituisce il valore base elevato alla potenza di exponent.

Genera un errore se base <= 0 e exponent sono negativi.
Per qualsiasi exponent, pow(1, exponent) è 1.
Per qualsiasi base, pow(base, 0) è 1.

Esempi:

base	base del logaritmo naturale	`pow(base, exponent)`
2	3	8.0
2	-3	0,125
`+inf`	0	1.0
1	`+inf`	1.0
-1	0,5	`[error]`
0	-1	`[error]`

Web

const googleplex = { latitude: 37.4221, longitude: 122.0853 };
const result = await execute(db.pipeline()
  .collection("cities")
  .addFields(
    field("lat").subtract(constant(googleplex.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("latitudeDifference"),
    field("lng").subtract(constant(googleplex.longitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("longitudeDifference")
  )
  .select(
    field("latitudeDifference").add(field("longitudeDifference")).sqrt()
      // Inaccurate for large distances or close to poles
      .as("approximateDistanceToGoogle")
  )
);test.firestore.js

Swift

let googleplex = CLLocation(latitude: 37.4221, longitude: 122.0853)
let result = try await db.pipeline()
  .collection("cities")
  .addFields([
    Field("lat").subtract(Constant(googleplex.coordinate.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("latitudeDifference"),
    Field("lng").subtract(Constant(googleplex.coordinate.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("longitudeDifference")
  ])
  .select([
    Field("latitudeDifference").add(Field("longitudeDifference")).sqrt()
      // Inaccurate for large distances or close to poles
      .as("approximateDistanceToGoogle")
  ])
  .execute()PipelineSnippets.swift

Kotlin

val googleplex = GeoPoint(37.4221, -122.0853)
val result = db.pipeline()
    .collection("cities")
    .addFields(
        field("lat").subtract(googleplex.latitude)
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("latitudeDifference"),
        field("lng").subtract(googleplex.longitude)
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("longitudeDifference")
    )
    .select(
        field("latitudeDifference").add(field("longitudeDifference")).sqrt()
            // Inaccurate for large distances or close to poles
            .alias("approximateDistanceToGoogle")
    )
    .execute()DocSnippets.kt

Java

GeoPoint googleplex = new GeoPoint(37.4221, -122.0853);
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("cities")
    .addFields(
        field("lat").subtract(googleplex.getLatitude())
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("latitudeDifference"),
        field("lng").subtract(googleplex.getLongitude())
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("longitudeDifference")
    )
    .select(
        field("latitudeDifference").add(field("longitudeDifference")).sqrt()
            // Inaccurate for large distances or close to poles
            .alias("approximateDistanceToGoogle")
    )
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

googleplexLat = 37.4221
googleplexLng = -122.0853
result = (
    client.pipeline()
    .collection("cities")
    .add_fields(
        Field.of("lat")
        .subtract(googleplexLat)
        .multiply(111)  # km per degree
        .pow(2)
        .as_("latitudeDifference"),
        Field.of("lng")
        .subtract(googleplexLng)
        .multiply(111)  # km per degree
        .pow(2)
        .as_("longitudeDifference"),
    )
    .select(
        Field.of("latitudeDifference")
        .add(Field.of("longitudeDifference"))
        .sqrt()
        # Inaccurate for large distances or close to poles
        .as_("approximateDistanceToGoogle")
    )
    .execute()
)firestore_pipelines.py

SQRT

Sintassi:

sqrt[N <: FLOAT64 | DECIMAL128](number: N) -> N

Descrizione:

Restituisce la radice quadrata di un number.

Genera un error se number è negativo.

Esempi:

numero	`sqrt(number)`
25	5,0
12.002	3,464…
0.0	0.0
`NaN`	`NaN`
`+inf`	`+inf`
`-inf`	`[error]`
`x < 0`	`[error]`

Web

const googleplex = { latitude: 37.4221, longitude: 122.0853 };
const result = await execute(db.pipeline()
  .collection("cities")
  .addFields(
    field("lat").subtract(constant(googleplex.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("latitudeDifference"),
    field("lng").subtract(constant(googleplex.longitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("longitudeDifference")
  )
  .select(
    field("latitudeDifference").add(field("longitudeDifference")).sqrt()
      // Inaccurate for large distances or close to poles
      .as("approximateDistanceToGoogle")
  )
);test.firestore.js

Swift

let googleplex = CLLocation(latitude: 37.4221, longitude: 122.0853)
let result = try await db.pipeline()
  .collection("cities")
  .addFields([
    Field("lat").subtract(Constant(googleplex.coordinate.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("latitudeDifference"),
    Field("lng").subtract(Constant(googleplex.coordinate.latitude))
      .multiply(111 /* km per degree */)
      .pow(2)
      .as("longitudeDifference")
  ])
  .select([
    Field("latitudeDifference").add(Field("longitudeDifference")).sqrt()
      // Inaccurate for large distances or close to poles
      .as("approximateDistanceToGoogle")
  ])
  .execute()PipelineSnippets.swift

Kotlin

val googleplex = GeoPoint(37.4221, -122.0853)
val result = db.pipeline()
    .collection("cities")
    .addFields(
        field("lat").subtract(googleplex.latitude)
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("latitudeDifference"),
        field("lng").subtract(googleplex.longitude)
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("longitudeDifference")
    )
    .select(
        field("latitudeDifference").add(field("longitudeDifference")).sqrt()
            // Inaccurate for large distances or close to poles
            .alias("approximateDistanceToGoogle")
    )
    .execute()DocSnippets.kt

Java

GeoPoint googleplex = new GeoPoint(37.4221, -122.0853);
Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("cities")
    .addFields(
        field("lat").subtract(googleplex.getLatitude())
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("latitudeDifference"),
        field("lng").subtract(googleplex.getLongitude())
            .multiply(111 /* km per degree */)
            .pow(2)
            .alias("longitudeDifference")
    )
    .select(
        field("latitudeDifference").add(field("longitudeDifference")).sqrt()
            // Inaccurate for large distances or close to poles
            .alias("approximateDistanceToGoogle")
    )
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

googleplexLat = 37.4221
googleplexLng = -122.0853
result = (
    client.pipeline()
    .collection("cities")
    .add_fields(
        Field.of("lat")
        .subtract(googleplexLat)
        .multiply(111)  # km per degree
        .pow(2)
        .as_("latitudeDifference"),
        Field.of("lng")
        .subtract(googleplexLng)
        .multiply(111)  # km per degree
        .pow(2)
        .as_("longitudeDifference"),
    )
    .select(
        Field.of("latitudeDifference")
        .add(Field.of("longitudeDifference"))
        .sqrt()
        # Inaccurate for large distances or close to poles
        .as_("approximateDistanceToGoogle")
    )
    .execute()
)firestore_pipelines.py

EXP

Sintassi:

exp(exponent: FLOAT64) -> FLOAT64

Descrizione:

Restituisce il valore del numero di Eulero elevato alla potenza di exponent, chiamato anche funzione esponenziale naturale.

Esempi:

base del logaritmo naturale	`exp(exponent)`
0.0	1.0
10	`e^10` (`FLOAT64`)
`+inf`	`+inf`
`-inf`	0

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("rating").exp().as("expRating"))
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("rating").exp().as("expRating")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(field("rating").exp().alias("expRating"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(field("rating").exp().alias("expRating"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("rating").exp().as_("expRating"))
    .execute()
)firestore_pipelines.py

LN

Sintassi:

ln(number: FLOAT64) -> FLOAT64

Descrizione:

Restituisce il logaritmo naturale di number. Questa funzione è equivalente a log(number).

Esempi:

numero	`ln(number)`
1	0.0
2L	0,693…
1.0	0.0
`e` (`FLOAT64`)	1.0
`-inf`	`NaN`
`+inf`	`+inf`
`x <= 0`	`[error]`

Web

const result = await execute(db.pipeline()
  .collection("books")
  .select(field("rating").ln().as("lnRating"))
);test.firestore.js

Swift

let result = try await db.pipeline()
  .collection("books")
  .select([Field("rating").ln().as("lnRating")])
  .execute()PipelineSnippets.swift

Kotlin

val result = db.pipeline()
    .collection("books")
    .select(field("rating").ln().alias("lnRating"))
    .execute()DocSnippets.kt

Java

Task<Pipeline.Snapshot> result = db.pipeline()
    .collection("books")
    .select(field("rating").ln().alias("lnRating"))
    .execute();DocSnippets.java

Python

from google.cloud.firestore_v1.pipeline_expressions import Field

result = (
    client.pipeline()
    .collection("books")
    .select(Field.of("rating").ln().as_("lnRating"))
    .execute()
)firestore_pipelines.py

LOG

Sintassi:

log(number: FLOAT64, base: FLOAT64) -> FLOAT64
log(number: FLOAT64) -> FLOAT64

Descrizione:

Restituisce il logaritmo di un number in base base.

Se viene fornito solo number, restituisce il logaritmo di number in base base (sinonimo di ln(number)).

Esempi:

numero	base	`log(number, base)`
100	10	2.0
`-inf`	`Numeric`	`NaN`
`Numeric`.	`+inf`	`NaN`
`number <= 0`	`Numeric`	`[error]`
`Numeric`	`base <= 0`	`[error]`
`Numeric`	1.0	`[error]`

LOG10

Sintassi:

log10(x: FLOAT64) -> FLOAT64

Descrizione:

Restituisce il logaritmo di un number in base 10.

Esempi:

numero	`log10(number)`
100	2.0
`-inf`	`NaN`
`+inf`	`+inf`
`x <= 0`	`[error]`

RAND

Sintassi:

rand() -> FLOAT64

Descrizione:

Restituisce un numero in virgola mobile pseudocasuale, scelto in modo uniforme tra 0.0 (incluso) e 1.0 (escluso).

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