What is difference between MAP and flatMap?
The difference is that the map operation produces one output value for each input value, whereas the flatMap operation produces an arbitrary number (zero or more) values for each input value.
What is difference between MAP and flatMap in Scala?
The flatMap() method is similar to the map() method, but the only difference is that in flatMap, the inner grouping of an item is removed and a sequence is generated. The flatMap method acts as a shorthand to map a collection and then immediately flatten it.
What is MAP and flatMap in spark?
Both map() and flatMap() are used for transformations. The map() transformation takes in a function and applies it to each element in the RDD and the result of the function is a new value of each element in the resulting RDD. The flatMap() is used to produce multiple output elements for each input element.
What is Scala flatMap?
In Scala, flatMap() method is identical to the map() method, but the only difference is that in flatMap the inner grouping of an item is removed and a sequence is generated. So, we can say that flatMap first runs the map method and then the flatten method to generate the desired result.
What is a flat map called?
a flat map that represents the three-dimensional curved surface of a globe is called a map projection. earth because a globe is spherical like earth, a globe can accurately represent the locations relative areas and relative shapes of earth’s surface features.
Why are flat maps used?
flatMap() is an intermediate operation and return another stream as method output return value. It returns a stream consisting of the results of replacing each element of the given stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
Where are map and flat maps used?
You should use a map() if you just want to transform one Stream into another where each element gets converted to one single value. Use flatMap() if the function used by map operation returns multiple values and you want just one list containing all values.
What is the difference between MAP and flatMap and a good use case for each?
As per the definition, difference between map and flatMap is: map : It returns a new RDD by applying given function to each element of the RDD. Function in map returns only one item. flatMap : Similar to map , it returns a new RDD by applying a function to each element of the RDD, but output is flattened.
What is map in spark Scala?
A map is a transformation operation in Apache Spark. Spark Map function takes one element as input process it according to custom code (specified by the developer) and returns one element at a time. Map transforms an RDD of length N into another RDD of length N.
What is a map in Scala?
Scala map is a collection of key/value pairs. Maps are also called Hash tables. There are two kinds of Maps, the immutable and the mutable. The difference between mutable and immutable objects is that when an object is immutable, the object itself can’t be changed. By default, Scala uses the immutable Map.
What is collect Scala?
The collect function is applicable to both Scala’s Mutable and Immutable collection data structures. The collect method takes a Partial Function as its parameter and applies it to all the elements in the collection to create a new collection which satisfies the Partial Function.
What is flat map in geography?
flat map that represents the three-dimensional curved surface of a globe is called a map projection. no projection is an entirely accurate representation of earth’s surface. however, each kind of projection has certain advantages and disadvantages that must be considered when choosing a map. cylindrical projections.