Get Random Values

Description

This operation returns the specified number of random values from a set.

Method

Objective-CSwift

[[[Backendless.shared hive:(NSString *)hiveName] setStore:(NSString *)keyName] setStore:@"transactions"] getRandomWithCount:(NSInteger)count responseHandler:^(NSArray *)responseHandler errorHandler:^(Fault *)errorHandler];

Backendless.shared.hive(hiveName: String).setStore(keyName: String).getRandom(count: Int, responseHandler: (([Any]) -> Void)!, errorHandler: ((Fault) -> Void)!)

where:

Argument	Description
hiveName	Name of a hive where the operation is performed. String value.
keyName	Key name identifying a set. String value.
count	Optional parameter. Identifies the number of values to return in the response. Defaults to 1. When the parameter value is a positive number, the  returned array contains only unique values. When the parameter value is negative, the returned array may include duplicate values.

Return Value

An array containing values from the set. Each individual value is of any data type. The operation applies the following rules that impact the returned value:

• If the count parameter is not used, then this operation returns only one random value from the set.
• When a positive number is passed to the count parameter, then the returned array contains unique elements from the set.
• In case a negative number is passed to the count parameter, then the operation's behavior changes, and the returned array may contain duplicate elements.

Examples

Return a Single Value

The example below returns a random value from the "cars" set.

Objective-CSwift

[[[Backendless.shared hive:@"transport"] setStore:@"cars"] getRandomWithResponseHandler:^(NSArray *response) {
    // handle response
} errorHandler:^(Fault *fault) {
    // handle error
}];

Backendless.shared.hive("transport").setStore("cars").getRandom(responseHandler: { response in
    // handle response
}, errorHandler: { fault in
    // handle error
})

where:

Argument	Description
"transport"	Name of a hive where the operation is performed.
"cars"	Key name identifying a set.

Return Multiple Unique Values

The example below returns five random values from the "cars" set. By specifying the count parameter you can change how many unique random values are returned.

Objective-CSwift

[[[Backendless.shared hive:@"transport"] setStore:@"cars"] getRandomWithCount:5 responseHandler:^(NSArray *response) {
    // handle response
} errorHandler:^(Fault *fault) {
    // handle error
}];

Backendless.shared.hive("transport").setStore("cars").getRandom(count: 5, responseHandler: { response in
    // handle response
}, errorHandler: { fault in
    // handle error
})

where:

Argument	Description
"transport"	Name of a hive where the operation is performed.
"cars"	Key name identifying a set.

Get Multiple Values with Duplicates

The example below returns four random values from the "cars" set. Since the count parameter is a negative value, the response may include duplicate values.

Objective-CSwift

[[[Backendless.shared hive:@"transport"] setStore:@"cars"] getRandomWithCount:-4 responseHandler:^(NSArray *response) {
    // handle response
} errorHandler:^(Fault *fault) {
    // handle error
}];

Backendless.shared.hive("transport").setStore("cars").getRandom(count: -4, responseHandler: { response in
    // handle response
}, errorHandler: { fault in
    // handle error
})

where:

Argument	Description
"transport"	Name of a hive where the operation is performed.
"cars"	Key name identifying a set.

You can find a sample response below demonstrating the presence of identical values.

[  
    "Sedan",  
    "Crossover",  
    "Crossover",  
    "Hatchback"  
]

Codeless Reference

where:

Argument	Description
hive name	Name of a hive where the operation is performed.
key name	Key name identifying a set.
count	Number of random items to get.

This operation returns a list containing random values from the set. If the count parameter is a positive number, the returned list contains unique random values from the set. If the parameter is a negative number, the returned list may contain duplicates.

Consider the following Set storage:

The example below retrieves a random value from the "cars" set:

The logic produces the following output: