delphi collections

[DataStructure] The description of generic collections, datastructure In this blog, generic collections will be talked about in details. in the past bacause of temporary age of generic argument, less importance has been attached to the this module. just now after reading the chapter about this knowledge, I gradually realized that they are so useful in the pactice, especially desgin the system achitect. now

comparator must use the treemap (ComparatorComparator) constructor. Collections class is a tool class for managing collections and graphs. Create a synchronization set and graph, create a read-only set and graph, create a set and graph of single element or element pair, and sort the list (SORT) and search (binarysearch), fill, shuffle, copy, and reverse, you can copy n copies of a value o to generate a lis

to true, output YesIf True or false and not false: print (' yes ') Else: print (' no ') output YesCollectionA collection is a relational operation that removes duplicate elements, and the elements can only be immutable, and the set and dictionary are unordered.Create a CollectionS1={1,2,2,3,4}print (S1,type (S1)) S2=set (' Apple ') print (S2,type (S2)) s3=set ([' Apple ', ' apple ', ' pear ') print (S3,type (S3)) S4=set (' Apple ', ' apple ', ' pear ') print (S4,type (S4)) S5=set ({' Appl

Here we introduce the usage of the defaultdict type in Python's collections module, the biggest difference from the built-in dictionary class is the initialization, and look at it together:The defaultdict is primarily used in situations where value initialization is required. For a dictionary, key must be hashable,immutable,unique data, and value can be any data type. If value is a data type such as list,dict, it must be initialized to null before use

The Java.util.Collections tool class provides a lot of practical methods. Makes it easier for programmers to manipulate collection classes, and these methods are static.The entire Collections tool class source code is almost identical to 4000 lines. We illustrate some of the typical approaches.1. Call an empty List,set,mappublicstaticfinalnew EmptyListpublicstaticfinalnew EmptyMappublicstaticfinalnew EmptySet2. AddAllpublic static Super t> C, T ... el

One, Collections moduleOn the basis of the built-in data types (dict, list, set, tuple), the collections module also provides several additional data types: Counter, deque, Defaultdict, Namedtuple, and Ordereddict.1.namedtuple: Generate a tuple that can access the content of an element by using a name2.deque: Double-ended queue to quickly append and eject objects from the other side3.Counter: Counter, mainl

1. Immutable data dictionary (nsdicionary)Dictionary: Used to store data with one by one correspondence.A key corresponds to a value, the key plays a unique role, the key must be unique, but a vlaue can correspond to multiple keys.Dictionaries store unordered elements, and a pair of key-value pairs make up an element in the dictionary.①. Immutable Dictionary initialization Assignment②. Find the number of dictionary elements, that is, get all the keys and value③. Traversal dictionary: Get key, an

();3ListNewArraylist(); 4Sortobject s1=NewSortobject (1,4);5Sortobject s2=NewSortobject (7,9);6Sortobject s3=NewSortobject (5,6);7 L.add (S1);8 l.add (S2);9 L.add (S3); Ten Collections.sort (l,my); OneIterator it =l.iterator (); A while(It.hasnext ()) { -Object obj =It.next (); - System.out.println (obj); the } - - } - +}Map Interface (Control key value pair):Meaning: Corresponds to a set of correspondence between a key (key) and a value (value).Two implementation classes

Programmers often misuse the copy constructors provided by each collection class as clones, List Set ArrayList HashSet or methods implemented by other collections. It should be remembered that the copy constructor for the Java collection only provides a shallow copy rather than a deep copy, which means that the objects stored in the original list and the clone list are the same, pointing to the same location in the Java heap memory. One of the reasons

Regular expressionsMeta-character quantifier (?)Metacharacters:.\w \d \s \w \d \s\ t \ \b() |[] [^]^ $Quantifiers:* + ?{n}, {n,}, {n,m}Re moduleHow to invoke the RE moduleFind: FindAll search match FinditerSplit and replace: Split Sub SubnCompile: Compile Save timeHow many places is the RE module used in?Quantifier: Indicates a match 0 or 1 timesAfter the quantifier: is the sign of the lazy matchGroup naming: (? pFindall/split Ungroup Priority: (?: Regular expression)

First, create a collection1. Featuresto store different elementsDisorderedImmutable types (numbers, strings, tuples)2. Create a CollectionS=set (' Hello ')Print (s)S=set ([' Alex ', ' Alex ', ' SB '])Print (s)s={1,2,3,4,5,6}3. Basic usage of sets(1) AddS.add (' s ')(2) ClearS.clear ()(3) CopyS.copy ()(4) DeleteRemove () Specifies to delete an element if the delete element does not exist then an errorDiscard (' sbbbb ') delete element not present no er

NodeListThe NodeList instance object is a class array object whose members are node objects, including the ChildNodes and Queryselectorall () method return valuesA dynamic collection is a change in the DOM structure that can be automatically reflected in the saved objectStaticNote NodeList are not all dynamic collections, where the Queryselectorall () return value is a static collection nodestaticlistArraySince nodelist is a class array object and not

The use of Java collection classes can be said to be ubiquitous, the total we can be divided into three chunks, respectively, from the collection interface extension of the list, set and the form of key-value pairs to store the map type collection. Many situations require that we iterate through the elements in the collection and do the appropriate processing. The following is a summary of the traversal of various types of collections, with regard to

1. Counter (counter)Counter is a dictionary method used to track the number of occurrences of a value, with all the functions and functions of a dictionary.>>> fromCollectionsImportCounter>>> D2 =Count>>> D2 = Counter ('abbcccddd')#Count of Values>>>Print(D2) Counter ({'D': 3,'C': 3,'b': 2,'a': 1})>>>Print(Type (D2))class 'collections. Counter'>>>> D2 = Counter ('abbcccddd')>>> forIinchD2.elements ():#count Element iterator...Print(i) ... bbadddccc>>>

Ever since JDK 1.2 collections are being widely used to store data in our programs. These Collection classes are used to store data which are shared by diferrent threads. Hence come the problem of which collection are. i.e. Operations on these collection classes are synchronized.If a collection class is isn't thread-safe and if we intend to use it in our multithreaded program, then we need to explicit Ely synchronize them. (or apply a wrapper class)So

The collections class contains a number of other useful utilities (such as Table II):Enumeration (Collection) produces the original style enumeration (enum) for the argumentMax (Collection), Min (Collection) produces the largest or smallest element in a natural comparison of objects within a set in an argumentMax (Collection,comparator), Min (collection,comparator) produces the largest or smallest element in a set with a comparerncopies (int n, Object

Since collections are a tool that we often use, a collection library is essential and should be easily reused. In this way, we can easily take various collections and insert them into our programs. Java provides such a library, although it appears to be very limited in Java 1.0 and 1.1 (the Java 1.2 Collection library is undoubtedly a masterpiece). 1. Next-tracing modelling and template/versatilityTo make

collections or containers usually we use arrays to hold some basic data types, arrays are types supported by compilers, but one obvious disadvantage of arrays is that they have fixed sizes, and in general, only when the program is running can we know the exact number to save. The Java class Library provides a fairly complete set of container frameworks (collections framework) to address this problem. The ba

Learn Python collections every dayLearn Python collections every day Based on the built-in data types (dict, list, set, and tuple), the collections module provides several additional data types: ChainMap, Counter, deque, defaultdict, namedtuple, and OrderedDict.ChainMap ChainMap is a new feature of python3. It is used to form multiple maps into a new unit (the o

Collections ModuleOn the basis of the built-in data type (DICT, list, set, tuple),The collections module also provides several additional data types: Counter, deque, Defaultdict, Namedtuple, and Ordereddict.1.namedtuple: Generate a tuple that can access the content of an element by using a name2.deque: Double-ended queue to quickly append and eject objects from the other side3.Counter: Counter, mainly used