Numbers, Data, and Basic Values:
1. struct Int - a signed integer value.
2. struct Double - a double-precision, floating-point value type.
3. struct Decimal - a structure representing a base 10 number.
4. class NumberFormatter - a formatter that converts berween numeric values and their textual representations.
5. struct Data - a byte buffer in memory.
6. struct URL - a value that identifies the location of a resource, such as an item on a remote server or the path to a local file.
7. struct URLComponents - a structure that parses URLs into and constructs URLs from their constutuent parts.
8. struct URLQueryItem - a single name value pair from the query portion of URL.
9. struct UUID - a universally unique value that canbe used to identify types, interfaces, and other items.
10. struct CGFloat - the basic type for floating-point scalar values in Core Graphics and related frameworks.
11. typealias NSPoint - a point in a Cartesian coordinate system.
12. typealias NSSize - a two-dimensional size.
13. typealias NSRect - a rectangle.
14. struct AffineTransfotm - a graphics coordinate transformation.
15. struct NSEdgeInsets - a description of the distance between the edges of two rectangles.
16. typealias NSRange - a structure used to describe a portion of a series, such as characters in a string in a string or objects in an array.

Strings and Text:
Create and process strings of Unicode characters, use regular expressions to find patterns, and perform natural language analysis of text.

1. struct String - a Unicode string value that is a collection of characters.
2. class NSAttibutedString - a string that has associated attributes (such as visual style, hyperlink, or accessibility data) associated with various portions of its text content.
3. struct ChatacterSet - a set of character values fot use in search operations.
4. typealies UnicodeScalar
5. class NSLinguisticTagger - Analyze natural language text to tag part of speech and lexical class, identify names, perform lemmatization, and determine the language and script
6. class Scanner - a string parser that scans for substring or characteristics in a character set, and for numeric values from decimal, hexadecimal, and floating-point representations.
7. class NSRegularExpression - an immutable representation of a compiled regulat expression that you apply to Unicode strings.
8. class NSDataDetector - a specialized regular expression object that matches natural language text for predefined data patterns.
9. class NSTextCheckingResult - an occurance of textual content found during the analysis of a block of text, such as when matching a regular expession.
10. Int NSNotFound - a value indicating that a requested item could not be found or does not exist.
11. class NSSpellServer - a server that your app uses to provide a spell checker service to other apps running in the system.
12. protocol NSSpellServerDelegate - the optional methods implemented by the delegate of a spell server.
13. struct Locale - information about linguistic, cultural, and technological conventions for use in formatting data for presentation.
14. class NSOrthography - a description of linguistic content of natural language text, typically used for spelling and grammar checking.
15. func NSLocalizedString(String, tableName: String?, bundle: Bundle, value: String, comment: String?) -> String - Returns a localized string, using the main bundle if one is not specified.

Collections
1. struct Array - an ordered, random-access collection.
2. struct Dictionary - a collection whose elements are key-value pairs.
3. struct Set - an unordered collection of unique elements.
4. struct IndexPath - a list of indexes that together represent the path to a specific location in a tree of nested arrays.
5. struct IndexSet - a collection of unique integer values that represent the indexes of elements in another collection.
6. class NSCountedSet - a mutable, unordered collection of distinct objects that may appear more than once in the collection.
7. class NSOrderedSet - a static, ordered collection of unique objects.
8. class NSMutableOrderedSet - a dynamic, ordered collection of unique objects.
9. class NSCache - a mutable collection you use to temporarily store transient key-value pairs that are subject to eviction when resources are low.
10. class NSPurgeableData - a mutable data object containing bytes that can be discarded when they're no longer needed.
11. class NSPointerArray - a collection similar to an array, but with a broader range of available memory semantics.
12. class NSMapTable - a collection similar to a dictionary, but with a broader range of available memory semantics.
13. class NSHashTable - a collection similar to a set, but with broader range of available memory semantics.
14. class NSEnumerator - an abstract class whose subclasses enumerate collections of objects, such as arrays and dictionaries.
15. protocol NSFastEnumeration - A protocol that objects adopt to support fast enumeration.
16. struct NSFastEnumerationIterator
17. struct NSIndexSetIterator - an iterator suitable for enumerating the elements of an index set.
18. struct NSEnumerationOptions - options for block enumeration operations.
19. struct NSSortOptions - options for block sorting operations.
20. class NSNull - a singleton object used to represent null values in collection objects that don’t allow nil values.
21. Int NSNotFound - a value indicating that a requested item couldn’t be found or doesn’t exist.

Dates and Times:
Compare dates and times, and perform calendar and time zone calculations.

1. struct Date - a specific point in time, independent of any calendar or time zone.
2. struct DateInterval - the span of time between a specific start date and end date.
3. typealias TimeInterval - a number of seconds.
4. struct DateComponents - a date or time specified in terms of units (such as year, month, day, hour, and minute) to be evaluated in a calendar system and time zone.
5. struct Calendar - a definition of the relationships between calendar units (such as eras, years, and weekdays) and absolute points in time, providing features for calculation and comparison of dates.
6. struct TimeZone - information about standard time conventions associated with a specific geopolitical region.
7. class DateFormatter - a formatter that converts between dates and their textual representations.
8. class DateComponentsFormatter - a formatter that creates string representations of quantities of time.
9. class DateIntervalFormatter - a formatter that creates string representations of time intervals.
10. class ISO8601DateFormatter - a formatter that converts between dates and their ISO 8601 string representations.
11. struct Locale - information about linguistic, cultural, and technological conventions for use in formatting data for presentation.

Units and Measurement:
Label numeric quantities with physical dimensions to allow locale-aware formatting and conversion between related units.

1. struct Measurement - a numeric quantity labeled with a unit of measure, with support for unit conversion and unit-aware calculations.
2. class Unit - an abstract class representing a unit of measure.
3. class Dimension - an abstract class representing a dimensional unit of measure.
4. class UnitConverter - an abstract class that provides a description of how to convert a unit to and from the base unit of its dimension.
5. class UnitConverterLinear - a description of how to convert between units using a linear equation.
6. class UnitArea - a unit of measure for area.
7. class UnitLength - a unit of measure for length.
8. class UnitVolume - a unit of measure for volume.
9. class UnitAngle - a unit of measure for rotation.
10. class UnitMass - a unit of measure for mass.
11. class UnitPressure - a unit of measure for pressure.
12. class UnitAcceleration - a unit of measure for acceleration.
13. class UnitDuration - a unit of measure for duration of time.
14. class UnitFrequency - a unit of measure for frequency.
15. class UnitSpeed - a unit of measure for speed.
16. class UnitEnergy - a unit of measure for energy.
17. class UnitPower - a unit of measure for power.
18. class UnitTemperature - a unit of measure for temperature.
19. class UnitIlluminance - a unit of measure for luminance.
20. class UnitElectricCharge - a unit of measure for electric charge.
21. class UnitElectricCurrent - a unit of measure for electric current.
22. class UnitElectricPotentialDifference - a unit of measure for electric potential difference.
23. class UnitElectricResistance - a unit of measure for electric resistance.
24. class UnitConcentrationMass - a unit of measure for concentration of mass.
25. class UnitDispersion - a unit of measure for an amount-of-substance fraction.
26. class UnitFuelEfficiency - a unit of measure for fuel efficiency.

Data Formatting:
Convert numbers, dates, measurements, and other values to and from locale-aware string representations.

1. {} Converting Between Swift Data Types and Strings - use formatters to convert Swift data types to their string representations and back.
2. class NumberFormatter - a formatter that converts between numeric values and their textual representations.
3. class PersonNameComponentsFormatter - a formatter that provides localized representations of the components of a person’s name.
4. struct PersonNameComponents - the separate parts of a person's name, allowing locale-aware formatting.
5. class DateFormatter - a formatter that converts between dates and their textual representations.
6. class DateComponentsFormatter - a formatter that creates string representations of quantities of time.
7. class DateIntervalFormatter - a formatter that creates string representations of time intervals.
8. class ISO8601DateFormatter - a formatter that converts between dates and their ISO 8601 string representations.
9. class ByteCountFormatter - a formatter that converts a byte count value into a localized description that is formatted with the appropriate byte modifier (KB, MB, GB and so on).
10. class MeasurementFormatter - a formatter that provides localized representations of units and measurements.
11. struct Locale - information about linguistic, cultural, and technological conventions for use in formatting data for presentation.
12. class Formatter - an abstract class that declares an interface for objects that create, interpret, and validate the textual representation of values.
13. class LengthFormatter - a formatter that provides localized descriptions of linear distances, such as length and height measurements.
14. class MassFormatter - a formatter that provides localized descriptions of mass and weight values.
15. class EnergyFormatter - a formatter that provides localized descriptions of energy values.

Filters and Sorting:
1. class NSPredicate - a definition of logical conditions used to constrain a search either for a fetch or for in-memory filtering.
2. class NSExpression - an expression for use in a comparison predicate.
3. class NSComparisonPredicate - a specialized predicate that you use to compare expressions.
4. class NSCompoundPredicate - a specialized predicate that evaluates logical combinations of other predicates.
5. class NSSortDescriptor - an immutable description of how to order a collection of objects based on a property common to all the objects.
6. enum ComparisonResult - constants that indicate sort order.

The Swift standard library defines a base layer of functionality for writing Swift programs, including:
Fundamental data types such as Int, Double, and String
Common data structures such as Array, Dictionary, and Set
Global functions such as print(_:separator:terminator:) and abs(_:)
Protocols, such as Collection and Equatable, that describe common abstractions.
Protocols, such as CustomDebugStringConvertible and CustomReflectable, that you use to customize operations that are available to all types.
Protocols, such as OptionSet, that you use to provide implementations that would otherwise require boilerplate code.