However, what you need here is just a new map with all the values being doubled, you can simply do: Thanks for contributing an answer to Stack Overflow! A pair of, first, all elements that satisfy predicate p and, second, all elements that do not. Optionally applies a binary operator to all elements of this collection, going left to right. For example, on the JVM, String is an alias for java.lang.String. Ben Challenor (bchallenor) said: The most important changes in the Scala 2.13 collections library are: The scala-collection-compat is a library released for 2.11, 2.12 and 2.13 that provides some new APIs from Scala 2.13 for the older versions. of decorators that allow converting between Scala and Java collections using asScala Solution Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Compares the size of this iterable collection to a test value. For instance Map("x" -> 24, . Returns a scala.collection.Stepper for the elements of this collection. Converts this iterable collection of pairs into two collections of the first and second half of each pair. and + and - have been moved from scala.collection.Set to scala.collection.immutable.Set. Accidentally put regular gas in Infiniti G37. Some of these identifiers are type aliases provided as shortcuts to commonly used classes. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. The new operations are provided via an implicit enrichment. As its name suggests, Already on GitHub? a new iterable collection resulting from applying the given partial function pf to each element on which it is defined and collecting the results. a strict builder for the same collection type. The equality method for reference types. Returns the runtime class representation of the object. The method as implemented here does not call size directly; its running time is O(size min otherSize) instead of O(size). The companion object of this map, providing various factory methods. Normal immutable collections ({{List}}, {{Vector}} etc.) of them. How to replace an Item in scala Map, keeping the order. Basically .mapView and .filterKeys are still lazy with no way to force. A future version will include a strict version of this method (for now, .view.mapValues(f).toMap). a new iterable collection resulting from concatenating all element iterable collections. ~1.3x faster than the version that uses mapValues. @retronym said: world outside of it. However, as long as that type is a subtype of. a iterable collection containing the elements greater than or equal to index from extending up to (but not including) index until of this iterable collection. This is the documentation for the Scala standard library. A view over the elements of this collection. Here are some common use cases for mapValues():. Reuse: After calling this method, one should discard the iterator it was called on. The resulting function runs action(this(x)) where this is defined. The official documentation on binary compatibility. The hashCode method for reference types. well as the interaction between finalize and non-local returns re-implementing a ton of operations. In the latter example, because the type argument is erased as part of compilation it is For instance, This method, which implements an abstract method of trait PartialFunction, is equivalent to contains. Not the answer you're looking for? See method stepper. Therefore, if two objects are references to each other (o1 eq o2), they scala.collection.immutable - Immutable . The resulting map wraps the original map without copying any elements. I like #2 best of all the "let's do something" options, but we don't have to deprecate anything in order to provide an eager alternative. You can use the compiler to do so by declaring Note: might return different results for different runs, unless the underlying collection type is ordered. On the java platform it Scala Standard Library 2.13.0 - scala.collection.StringOps This data structure supports constant time index access, and amortized constant time This might cause unexpected results sometimes. Thanks for contributing an answer to Stack Overflow! the iterable providing the second half of each result pair. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Will return the same collection if this instance is already Iterable. true if the given predicate p is satisfied by at least one element of this collection, otherwise false. Add configurable protection against server-bug induced resets. A Guide to Scala Maps | Baeldung on Scala When implementing a custom collection type and refining C to the new type, this method needs to be overridden (the compiler will issue an error otherwise). A simple if else logic should do the trick, Or a simple match case should do the trick as well as explained by @rogue-one. the element type of the first resulting collection, the element type of the second resulting collection, the 'split function' mapping the elements of this iterable collection to an scala.util.Either. Selects all elements of this view which do not satisfy a predicate. type: The most common way to create a collection is to use its companion object as (A deprecated element the result of inserting op between consecutive elements of this collection, going left to right: op( op( op(x1, x2) , xn-1), xn) where x1, , xn are the elements of this collection. For example: the type of the elements of each iterable collection. So maybe the best way forward would be to add eager methods with a similar name? Kafka Stream's transformations contain operations such as `filter`, `map`, `flatMap`, etc. For a non-strict collection such as, Note: many collection methods will not work on collections of infinite sizes. A deprecation warning is issued upon usage of the annotated definition. the type of keys returned by the discriminator function. according to the type of elements returned by the transformation function f. We believe that the new API is simpler to understand. Reduces the elements of this collection, if any, using the specified associative binary operator. The very idea of a lens is to be able to zoom in on a particular part of an immutable structure, and be able to 1) retrieve the smaller part from a larger structure, or 2) create a new . I agree with @Ichoran that "adding strict alternative" is technically orthogonal to the deprecation. So you can create it unwittingly, but you can't use it unwittingly. An annotation that designates that a definition is deprecated. the type of the second half of the returned pairs, The iterable providing the second half of each result pair. This means that an element deprecated in some 2.13.x release will be preserved in and will be removed in 2.14. Bumped into this in 2.9.2 and thought, "I'll just throw .seq onto the result". Produces a collection containing cumulative results of applying the operator going right to left. returns a TreeMap, but if there is no such Ordering instance then the best Any suggestion or doc I need to read about this? This article summarizes what is going @Blaisorblade said: and only copy data if the sequence wasnt immutable: The second, intermediate, migration strategy would be to change all methods to accept not-immutable Seq but * `immutable.Seq` or `collection.Seq` instead. But @dragos is right if the overall goal of the bug is not "offer both behaviors at all" but "fix latent bugs where clients use the lazy variant but shouldn't". The resulting collection's type will be guided by the static type of iterable collection. rev2023.7.7.43526. is using the fully-qualified _root_.scala.collection.Seq. a new collection of type That containing pairs consisting of corresponding elements of this iterable collection and that. I'd like to add another vote for this. For all partial function literals the compiler generates an applyOrElse implementation which avoids double evaluation of pattern matchers and guards. a class object corresponding to the runtime type of the receiver. the type of the first member of the element triples, the type of the second member of the element triples, the type of the third member of the element triples. in general is discouraged when working with Futures and concurrency in order to avoid hashcode in hexadecimal. The package object scala.sys contains methods for reading Note that this method is overridden in subclasses and the return type is refined to S with EfficientSplit, for example scala.collection.IndexedSeqOps.stepper. One more article about the standard collections, really? For non-literal partial function classes with nontrivial isDefinedAt method it is recommended to override applyOrElse with custom implementation that avoids double isDefinedAt evaluation. either an implicit or explicit ExecutionContext to be provided: Although blocking is possible in order to await results (with a mandatory timeout duration): and although this is sometimes necessary to do, in particular for testing purposes, blocking Iterable Is The Top Collection Type. the collection elements (e.g. a scala.collection.Traversable or scala.collection.Iterable, as Example uses: xs.to(List) xs.to(ArrayBuffer) xs.to(BitSet) // for xs: Iterable[Int]. scala> res0.mapValues(x=> x^2) res7: scala.collection.immutable.Map[String,Int] = Map(32 -> 1) 2.13: scala> res0.mapValues(x=> x^2).toMap ^ warning: method mapValues in trait MapOps is deprecated (since 2.13.0): Use .view.mapValues(f). Scala mapValues function. Instead, use callbacks or combinators to Aaron Novstrup (anovstrup) said: and exceptions, are all platform dependent. is that several types or operations have been deprecated in Scala 2.13 For numerics, it returns a hash value which is consistent The returned iterator will be empty when called on an empty collection. operations are suffixed with InPlace. This suggestion is invalid because no changes were made to the code. I'm not sure what createMap() function returns, but my guess is that it returns a Map[String, Int].. java-friendly interface that don't rely on implicit enrichments. the argument type of the fallback function. collection and the type of elements of the new collection. For numerics, it returns a hash value which is consistent Called by the garbage collector on the receiver object when there This ticket is nr. This package object contains primitives for concurrent and parallel programming. increment their age, one can now write: A consequence of cleaning and simplifying the collections framework a partial function with the domain of this partial function narrowed by other partial function, which maps arguments x to k(this(x)). a string representation of this collection. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. views should behave in a more predictable way. We could maybe also document how to perform this operation in a strict way (.view.filterKeys(p).toMap)? Called by the garbage collector on the receiver object when there the method toString) of all elements of this collection, separated by the string sep. Appends all elements of this map to a string builder using start, end, and separator strings. Cast the receiver object to be of type T0. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters. Different maturities but same tenor to obtain the yield, Typo in cover letter of the journal name where my manuscript is currently under review. Extract data which is inside square brackets and seperated by comma, Sci-Fi Science: Ramifications of Photon-to-Axion Conversion. true if the receiver object is equivalent to the argument; false otherwise. Creates a non-strict filter of this view. Applies a binary operator to all elements of this collection, going right to left. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. representation is platform dependent. imports. @deprecated("Use view.filterKeys. Displays all elements of this collection in a string. If that is shorter than this iterable collection, thatElem values are used to pad the result. rev2023.7.7.43526. a pair of iterable collections: the first one made of those values returned by f that were wrapped in scala.util.Left, and the second one made of those wrapped in scala.util.Right. Applies a binary operator to a start value and all elements of this collection, going left to right. They can be used directly as shown below since their companion objects are In the movie Looper, why do assassins in the future use inaccurate weapons such as blunderbuss? (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), The following table summarizes the breaking changes. By default this string consists of the className of this view, followed by all elements separated by commas and enclosed in parentheses. val mymap = Map (1 -> "james",2 -> "justin") println (mymap.view.mapValues (x => "hi" + x).toMap) println (mymap.view.mapValues (x => x.toUpperCase).toMap) Note that in Scala 2.12 calling mapValues returned a Map. should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode). Otherwise, this is the perfect opportunity Partitions this iterable collection into a map of iterable collections according to a discriminator function key. We read every piece of feedback, and take your input very seriously. Having all these operations can be handy in some cases but can also introduce confusion. You signed in with another tab or window. described in the parallel collections guide. This is the documentation for the Scala standard library. * to make defining these easier: Basic use of futures is easy with the factory method on Future, which executes a Tests whether this map contains a binding for a key. Builds a new map by applying a function to all elements of this map. A more detailed guide to Futures and Promises, including discussion and examples These implementations have specific performance The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports. how to cross-build projects with Scala 2.11 / 2.12 and 2.13. Format strings are as for String.format remain in the future domain: The package object scala.math contains methods for performing basic true if there is a binding for key in this map, false otherwise. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code. the result of this function or fallback function application. Composes two instances of Function1 in a new Function1, with this function applied last. Splits this iterable collection into a prefix/suffix pair at a given position. the type of values returned by the transformation function, the type of keys returned by the discriminator function. The Scala team has decided to enact a special deprecation policy for the 2.12 release: As an upgrade from Scala 2.11 to Scala 2.12 also requires upgrading from Java 6 to Java 8, Scala's Map is a collection of key-value pairs, where each key needs to be unique. It is convenient to treat all collections as either Composes this partial function with an action function which gets applied to results of this partial function. Returns a iterable collection formed from this iterable collection and another iterable collection by combining corresponding elements in pairs. the Iterable whose size is compared with this iterable collection's size. The scala package contains core types like Int, Float, Array Counts the number of elements in the collection which satisfy a predicate. true if the receiver object is an instance of erasure of type T0; false otherwise. Can the Secret Service arrest someone who uses an illegal drug inside of the White House? side effects. Yes, I was thinking of the following: For scala.collection.immutable.HashMap it would be possible (and pretty trivial) to write a mapValuesNow that is very high performance. not have to call hashCode or equals at all, whereas the generic mapValuesNow method calls them a lot and rebuilds the entire Trie from scratch. For instance, Map.map is overloaded: Type inference has been improved so that Map(1 -> "a").map(x => (x._1 + 1, x._2)) works, the compiler can infer the parameter type for the function literal. Inside, the string representations (w.r.t. and if you do need the laziness, perhaps you can .iterator your way to laziness. return immutable Seq, following the robustness principle (also known as Postels law): The third migration strategy is to change your API to use immutable sequences for both parameter and result a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication). The head of the collection is the last cumulative result. The order of the elements is preserved. The order of the elements is preserved. Cast the receiver object to be of type T0. each of the three basic collection types. Other aliases refer to classes provided by the underlying platform. Converts this iterable collection to an unspecified Iterable. a pair of iterable collections consisting of the first n elements of this iterable collection, and the other elements. {filterKeys,mapValues} while undeprecating those in MapView, Learn more about bidirectional Unicode characters, https://scala-ci.typesafe.com/job/scala-2.13.x-validate-main/3621/, [#10919] Deprecate Map. The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports.. the method, The resulting string begins with the string. now work with non-strict collections (such as View or Stream). a factory. old 2.12 List API, the signature You can find more details about that in Have a question about this project? filterKeysNow is a bit more complex, but you could probably reuse some of the filter code of HashSet. The eq method implements an equivalence relation on worth it, so we removed Traversable (it is now an alias to Iterable[A]). A view over a slice of the elements of this collection. the largest element of this collection with respect to the ordering ord. Copy elements to an array, returning the number of elements written. Implicit conversion to Iterable[(A, B)] is also supported. mutable collection types do not inherit immutable insertion and removal operations. How to format a JSON string as a table using jq? Partitions this iterable collection into a map of iterable collections according to some discriminator function. When working with Futures, you will often find that importing the whole concurrent Connect and share knowledge within a single location that is structured and easy to search. not specified by SLS as a member of AnyRef. To see all available qualifiers, see our documentation. scala.collection.immutable - Immutable . a new map resulting from applying the given partial function pf to each element on which it is defined and collecting the results. a string representation of this collection. makes it possible to apply some optimizations that make it The scala package contains core types like Int, Float, Array Is speaking the country's language fluently regarded favorably when applying for a Schengen visa? Other packages exist. Indices start at 0. the result type of the default computation. Package structure . * This `Seq` trait is a dummy type to prevent the use of `Seq`. How can I remove a mystery pipe in basement wall and floor? strict collections (such as List) and non-strict collections (such as Stream). the element to be used to fill up the result if that is shorter than this iterable collection. (this == that), false otherwise. Equivalent to x.hashCode except for boxed numeric types and null. Library authors should state the library's deprecation policy in their documentation to give the number of elements in this collection. collection type that can be returned is Map. @Blaisorblade said: In revision 21018, filterKeys and mapValues started returning map views in everything but name. All strict collections are known to have finite size. Find centralized, trusted content and collaborate around the technologies you use most. well as the interaction between finalize and non-local returns For collections of Int, Short, Byte or Char, an scala.collection.IntStepper is returned, For collections of Double or Float, a scala.collection.DoubleStepper is returned, For collections of Long a scala.collection.LongStepper is returned, For any other element type, an scala.collection.AnyStepper is returned. The method should be overridden if computing size is cheap and knownSize returns -1. is the concatenation of the class name, "@", and the object's The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. users whose name start with the letter J from a buffer and then Omer van Kloeten (omervk) said: a pair consisting of the longest prefix of this iterable collection whose elements all satisfy p, and the rest of this iterable collection. Indeed, the previous Partitions this iterable collection into a map according to a discriminator function key. all 2.13.x releases, but may be removed in the future. If n is negative, don't drop any elements. To learn more, see our tips on writing great answers. NoSuchElementException If the iterable collection is empty. Find centralized, trusted content and collaborate around the technologies you use most. Scala Standard Library 2.13.11 - scala.collection.Map For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams. sequences to varargs methods). The typical failure mode is an infinite loop. This may result in better performance and more predictable behavior w.r.t. an option value containing the first element in the collection that satisfies p, or None if none exists. Wakes up all threads that are waiting on the receiver object's monitor. can be found at Affected Versions: 2.8.0, 2.8.1, 2.9.0, 2.9.1, 2.11.1 I would be in favour of adding mapValuesNow, which already exists on s.c.i.AnyRefMap and s.c.i.LongMap. release to ease migration and upgrades from older Scala versions. I believe this will be quite visible despite our previous Partitions this iterable collection into a map according to a discriminator function key. If we can't fix mapValues and filterKeys, let's add mapValuesNow and filterKeysNow as Rdiger suggests. the various possible return types. because even if its a one-line change it causes name confusion. Already on GitHub? groupMapReduce is equivalent to groupBy(key).mapValues(_.map(f).reduce(g)). For null returns a hashcode where null.hashCode throws a not specified by SLS as a member of AnyRef. MapValues - EPFL Drops longest prefix of elements that satisfy a predicate. Note that the success of a cast at runtime is modulo Scala's erasure semantics. Compares the size of this iterable collection to the size of another Iterable. Creates a String representation of this object. we might eventually move them. the message to print during compilation if the definition is accessed, a string identifying the first version in which the definition was deprecated. an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate p. The resulting map wraps the original map without copying any elements. a new view consisting of all elements of this view that satisfy the given predicate p. The order of the elements is preserved. to be overridden by non-strict collection types. Programming MapValues the result of inserting op between consecutive elements of this collection, going right to left: op(x1, op(x2, , op(xn-1, xn))) where x1, , xn are the elements of this collection. val map = Map ("number"->7,"name"->"Jane","city"->"New York") I need to identify the "name" key for each record and check its value.If value is "Jane" , I need to replace with "Doe" and update the map record. Returns a new map containing the elements from the left hand operand followed by the elements from the right hand operand. In case youve thoroughly followed our previous blog posts and talks, you might pairs into something that is not even a pair, then the best collection type the result of inserting op between consecutive elements of this collection, going right to left with the start value z on the right: op(x1, op(x2, op(xn, z))) where x1, , xn are the elements of this collection. The length of the returned collection is the minimum of the lengths of this iterable collection and that. dictionary - modify scala map values - Stack Overflow List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)". Creates a view over all keys of this map. An ordering to be used for comparing elements. As a consequence, operations should preferably be implemented with fromSpecific instead of this method. They are always available without an explicit import. An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise. See hashCode in scala.Any. Contains the base traits and objects needed to use and extend Scala's collection library. and altering core aspects of the virtual machine as well as the the function exercise1 can running. scala.collection.Iterator, method sliding, List(1, 2, 3, 4, 5).sliding(2, 2) = Iterator(List(1, 2), List(3, 4), List(5)), List(1, 2, 3, 4, 5, 6).sliding(2, 3) = Iterator(List(1, 2), List(4, 5)). How do I do a Map comprehension with Scala? The official documentation on binary compatibility. ExecutionContext should be used. This method is deprecated in 2.13 because it does not provide any actionable information. We recommend using import scala.collection/import scala.collection.immutable and 18 months a lot of work has been done on the collections side and weve published true if ! Collections Additional comment actions. An Iterable containing all elements of this iterable collection. to use + or -, then you probably wanted to use an immutable collection type in the first place to add and remove entries. It doesn't work. Can Visa, Mastercard credit/debit cards be used to receive online payments? Produces a iterable collection containing cumulative results of applying the operator going left to right, including the initial value.

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