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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

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

1. Using a stream to traverse a collectionBrief introduction:Java's collection framework, such as the list and map interfaces and the ArrayList and HashMap classes, makes it easy to manage both ordered and unordered collections. The collection framework has been continuously improved since the first day of introduction. In Java SE 8, we can manage, traverse, and aggregate collections through the flow's API.

. 1. java. util. collection is Set Interface. It provides common interface methods for basic operations on collection objects. The collection interface has many specific implementations in the Java class library. The collection interface provides a unified operation mode to maximize various specific sets. Collection Shortlist │ Invalid parameter list │ ├ Arraylist │ Vector │ Elastic Stack Collections set 2 and Java. util.

The difference between the two:Both are interfaces;Collectoin is a top-level interface of the Java Collection framework, and the stored elements can be any type of object;Map is a map interface of the Java collection framework that stores objects in the form of key-value pairs;That is, the element stored in collection is an object, and map is the stored element that is a pair of pair of key-value pairs.CollectionMapC.add ("Hello");C.add ("World");Map.put (1, "Beijing");Map.put (2, "tianjing");Co

Collection is the ancestor interface of the collection class, and the main interface for inheriting it is set and list.Collections is a helper class for a collection class that provides a series of static methods for searching, sorting, threading, and so on for various collections.Collections This class consists entirely of static methods that operate on collection or return collectionCollection is a collection interface, collections is a wrapper clas

Java-collection framework Collections. sort (), Comparable interface, and Comparator interface, javasortcomparator Collentions tool class -- java. util. Collections Collentions is a tool class used to operate collection objects in the Java Collection framework. It is also a member of the Java Collection framework and is in parallel with List, Map, and Set. Collection