Reference.Random History

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May 31, 2010, at 06:30 PM by Equipo Traduccion -
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Description

The random function generates pseudo-random numbers.

Syntax

to:

Descripción

La función random genera números pseudoaleatorios.

Sintaxis

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Parameters

min - lower bound of the random value, inclusive (optional)

max - upper bound of the random value, exclusive

Returns

a random number between min and max-1 (long)

Note:

If it is important for a sequence of values generated by random() to differ, on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number, before starting the random sequence.

Example

to:

Parámetros

min - límite inferior del valor aleatorio, inclusive (opcional)

max - límite superior del valor aleatorio, exclusive (se devuelve hasta el anterior)

Devuelve

un número aleatorio entre min y max (long)

Nota:

Si es importante que la secuencia de valores generada por random() difiera en ejecuciones sucesivas de un programa, es recomendable utilizar randomSeed() (seed en inglés, semilla) para inicializar el generador de números aleatorios con una entrada mínimamente aleatoria como analogRead() en un pin desconectado.

No obstante, puede ser útil usar secuencias pseudoaleatorias que se repitan exactamente. Esto se consigue llamando a randomSeed() con un número fijo antes de empezar la generación de la secuencia.

Ejemplo

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long randNumber;

to:

long numAleatorio;

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  // if analog input pin 0 is unconnected, random analog
  // noise will cause the call to randomSeed() to generate
  // different seed numbers each time the sketch runs.
  // randomSeed() will then shuffle the random function.
to:
  // si la entrada analógica 0 no está conectada,
  // la llamada a randomSeed() recibirá ruido estático
  // (analógico) y se generarán diferentes semillas
  // cada vez que se ejecute el sketch.
Changed lines 38-45 from:
  // print a random number from 0 to 299
  randNumber = random(300);
  Serial.println(randNumber);  

  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);
to:
  // escribe un número aleatorio de 0 a 299
  numAleatorio = random(300);
  Serial.println(numAleatorio);  

  // escribe un número aleatorio de 10 a 19
  numAleatorio = random(10, 20);
  Serial.println(numAleatorio);
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See also

to:

Ver también

December 24, 2009, at 04:04 AM by David A. Mellis -
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long random(max)
long random(min, max)

to:

random(max)
random(min, max)

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long - a random number between min and max - 1

to:

a random number between min and max-1 (long)

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to:
October 13, 2008, at 05:11 PM by David A. Mellis -
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long random(max)

to:

long random(max)\\

October 13, 2008, at 05:10 PM by David A. Mellis -
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long random(max)
long random(min, max)

to:

random()

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Syntax

long random(max) long random(min, max)

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min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional)

September 27, 2007, at 06:06 AM by Paul Badger -
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If it is important for sequence of values generated by random() to differ on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

to:

If it is important for a sequence of values generated by random() to differ, on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

September 27, 2007, at 05:53 AM by Paul Badger -
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  // noise will cause the calls to randomSeed() to generate
to:
  // noise will cause the call to randomSeed() to generate
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  // randomSeed() then shuffles the random function
to:
  // randomSeed() will then shuffle the random function.
September 27, 2007, at 05:51 AM by Paul Badger -
September 27, 2007, at 05:50 AM by Paul Badger -
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Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

to:

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number, before starting the random sequence.

September 27, 2007, at 05:49 AM by Paul Badger -
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min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional parameter)

September 27, 2007, at 05:49 AM by Paul Badger -
Changed lines 8-9 from:

min - lower bound of the random value, inclusive (optional parameter)

to:

min - lower bound of the random value, inclusive (optional parameter)

September 27, 2007, at 05:48 AM by Paul Badger -
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min - lower bound on the random value, inclusive (optional)

max - upper bound on the random number, exclusive

to:

min - lower bound of the random value, inclusive (optional parameter)

max - upper bound of the random value, exclusive

September 27, 2007, at 05:46 AM by Paul Badger -
Changed lines 26-27 from:
  Serial.begin(19200);
to:
  Serial.begin(9600);
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  delay(50);
September 27, 2007, at 05:44 AM by Paul Badger -
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September 27, 2007, at 05:44 AM by Paul Badger -
Changed lines 29-30 from:
  // noise will cause the calls to random() to generate
  // different numbers each time the sketch runs.
to:
  // noise will cause the calls to randomSeed() to generate
  // different seed numbers each time the sketch runs.
  // randomSeed() then shuffles the random function
Deleted lines 35-38:
  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);
Added lines 38-42:
  Serial.println(randNumber);  

  // print a random number from 10 to 19
  randNumber = random(10, 20);
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September 27, 2007, at 05:41 AM by Paul Badger -
Changed lines 18-19 from:

Conversely, it can occasionally be useful to use sequences pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

to:

Conversely, it can occasionally be useful to use pseudo-random sequences that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

Changed lines 28-29 from:
  // if analog input pin 0 is unconnected, this
  // will cause the calls to random() to generate
to:
  // if analog input pin 0 is unconnected, random analog
  // noise will cause the calls to random() to generate
September 27, 2007, at 05:00 AM by David A. Mellis -
Changed lines 5-6 from:

The random function allows convenient access to pseudo-random numbers for use in sketches.

to:

The random function generates pseudo-random numbers.

Changed lines 8-21 from:

min - optional starting range (ie: from "50" - 300).

max - the largest random number returned (plus one).

In the current version of this function, the max parameter will not be returned, although the minimum will, so for example:

random(10); // returns numbers from 0 to 9

random(-5, 5); // returns numbers from -5 to 4

Consequently, enter a maximum parameter one larger than the maximum integer desired.

min and max are long integers so numbers between -2,147,483,648 and 2,147,483,647 are valid.

to:

min - lower bound on the random value, inclusive (optional)

max - upper bound on the random number, exclusive

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long - the random number.

to:

long - a random number between min and max - 1

Changed lines 16-19 from:

If it is important for a random number sequence to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely, it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with the same number as a parameter.

to:

If it is important for sequence of values generated by random() to differ on subsequent executions of a sketch, use randomSeed() to initialize the random number generator with a fairly random input, such as analogRead() on an unconnected pin.

Conversely, it can occasionally be useful to use sequences pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with a fixed number.

Added lines 27-31:
  // if analog input pin 0 is unconnected, this
  // will cause the calls to random() to generate
  // different numbers each time the sketch runs.
  randomSeed(analogRead(0));
Changed lines 34-42 from:

void loop(){

  randomSeed(analogRead(0));
  // return a random number from 50 - 300
  randNumber = random(50,301);

  // example with only a range, which would return
  // a number between 0 - 300
  // randNumber = random(301);
  Serial.println(r);
to:

void loop() {

  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);

  // print a random number from 0 to 299
  randNumber = random(300);
  Serial.println(randNumber);
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to:
September 27, 2007, at 04:37 AM by Paul Badger -
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max - the largest random numbers you'd like returned.

to:

max - the largest random number returned (plus one).

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Consequently, enter a maximum parameter one larger than the maximum integer dersired.

to:

Consequently, enter a maximum parameter one larger than the maximum integer desired.

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long - returns the random number.

to:

long - the random number.

Changed lines 26-29 from:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed with the same number.

to:

If it is important for a random number sequence to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

Conversely, it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed() with the same number as a parameter.

September 27, 2007, at 04:31 AM by Paul Badger -
Changed lines 42-43 from:
  randNumber = random(50,300);
to:
  randNumber = random(50,301);
Changed line 46 from:
  // randNumber = random(300);
to:
  // randNumber = random(301);
September 27, 2007, at 04:31 AM by Paul Badger -
Changed lines 26-27 from:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something for a parameter that is fairly random, such as millis(), or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:30 AM by Paul Badger -
Changed lines 25-26 from:

Note: If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

Note:

If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:29 AM by Paul Badger -
Changed lines 25-26 from:

Note: If it is important for a random number series to begin on a random number then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

to:

Note: If it is important for a random number series to begin on a random number, then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

September 27, 2007, at 04:29 AM by Paul Badger -
Changed lines 5-6 from:

The random function allows convenient access to pseudo-random numbers for use in an applications. NOTE: Use this after using the randomSeed() function.

to:

The random function allows convenient access to pseudo-random numbers for use in sketches.

Changed lines 12-13 from:

In the current version of this function, the max parameter will not be returned, although the minimum will so, for example:

to:

In the current version of this function, the max parameter will not be returned, although the minimum will, so for example:

random(10); // returns numbers from 0 to 9

Changed lines 18-19 from:

Consequently enter a maximum parameter one more than the meximum dersired.

to:

Consequently, enter a maximum parameter one larger than the maximum integer dersired.

Added lines 25-28:

Note: If it is important for a random number series to begin on a random number then call the randomSeed() function using something that is fairly random such as millis() or analogRead() on a pin with no electrical connection.

Conversely it can occasionally be useful to use pseudo-random numbers that repeat exactly. This can be accomplished by calling randomSeed with the same number.

September 27, 2007, at 04:17 AM by Paul Badger -
Changed lines 5-6 from:

The random function allows you to return pseudo-random numbers for use in your applications. NOTE: Use this after using the randomSeed() function.

to:

The random function allows convenient access to pseudo-random numbers for use in an applications. NOTE: Use this after using the randomSeed() function.

Changed lines 10-11 from:

max - the overall range of random numbers you'd like returned.

to:

max - the largest random numbers you'd like returned.

In the current version of this function, the max parameter will not be returned, although the minimum will so, for example:

random(-5, 5); // returns numbers from -5 to 4

Consequently enter a maximum parameter one more than the meximum dersired.

September 27, 2007, at 03:23 AM by Paul Badger -
Added lines 12-13:

min and max are long integers so numbers between -2,147,483,648 and 2,147,483,647 are valid.

May 27, 2007, at 02:33 AM by Paul Badger -
May 27, 2007, at 02:32 AM by Paul Badger -
Deleted lines 39-40:
May 08, 2007, at 07:22 PM by David A. Mellis -
Deleted line 17:

int time;

Changed lines 25-26 from:
  time = millis();
  randomSeed(time);
to:
  randomSeed(analogRead(0));
September 15, 2006, at 06:21 PM by David A. Mellis -
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long random(max)

long random(min, max)

to:

long random(max)
long random(min, max)

September 15, 2006, at 06:21 PM by David A. Mellis -
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long random([min,] max)

to:

long random(max)

long random(min, max)

September 11, 2006, at 05:15 PM by Jeff Gray -
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long random([start,] range)

to:

long random([min,] max)

Changed lines 7-10 from:

start - optional starting range (ie: from "50" - 300).

range - the overall range of random numbers you'd like returned.

to:

min - optional starting range (ie: from "50" - 300).

max - the overall range of random numbers you'd like returned.

September 11, 2006, at 05:05 PM by Jeff Gray -
Added lines 29-32:
  // example with only a range, which would return
  // a number between 0 - 300
  // randNumber = random(300);
September 11, 2006, at 05:04 PM by Jeff Gray -
Added lines 1-38:

long random([start,] range)

Description

The random function allows you to return pseudo-random numbers for use in your applications. NOTE: Use this after using the randomSeed() function.

Parameters

start - optional starting range (ie: from "50" - 300).

range - the overall range of random numbers you'd like returned.

Returns

long - returns the random number.

Example

int time;
long randNumber;

void setup(){
  Serial.begin(19200);
}

void loop(){
  time = millis();
  randomSeed(time);
  // return a random number from 50 - 300
  randNumber = random(50,300);
  Serial.println(r);
}

See also

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