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Definition and Creation of Functions  Function is the basic program structure provided by Python to maximize code reuse and minimize code redundancy; it allows programmers toComplex systems are decomposed into manageable components. Four functions can be created in Python:Global functions: defined in templatesLocal functions: nested in oth ...

Map Return type Method describe V get(Object key) Get value by key V put(Obejct k,Object v) Add (replace) elements to the Map and return the previous Value; return null without previous elements V remove(Object key) Delete the element according to key and return the value corresponding to Value void clear() empty int size() Get th ...

Set. Disorder, No Repetition HashSet Features: There is no duplicate data, and the data is not output in the order of storage. HashSet is supported by Hash table structure. The iteration order of set is not supported and the order is not guaranteed. But Hash table structure queries are fast. Create collection usage code: Set<String> s ...

In this paper, Python statistical simulation method is used to introduce four commonly used statistical distributions, including discrete distribution: binomial distribution and Poisson distribution, and continuous distribution: exponential distribution and normal distribution. Finally, the distribution of height and weight data is checked. # I ...

The article was originally created by the author. If it is reproduced, please indicate the source. If it is the same, it is the same. ~ (who care!) 1. Write before This is the first part of the Source Analysis Program. The blogger is going to pass through some of the commonly used collection sources, such as ArrayList, HashMap and their corresp ...

Introductionpython provides us with five basic data structures: list, tuple, dict, set, string;Sometimes we need to maintain an orderly dict. So at this time, we will use the collection package provided by Python standard library. It provides many useful collection classes. Mastering these collection classes skillfully can not only make our cod ...

The length of the array is immutable and data with mapping relationships cannot be saved. Java provides collections, which are mainly responsible for saving and filling other elements. Therefore, collection classes are also called container classes. Arrays can hold basic data types and objects, while collections can only hold objects. The col ...

The singleton pattern guarantees that the object is unique in memory public class Singleton{ private static final Singleton singleObject = new Singleton(); private Singleton(){} public static getSingleton(){ return singleObject; } } The hungry man pattern creates object instances the first time this class is ...

Python serialization and deserialization By serializing the object, it can be stored in variables or files, and the state of the object at that time can be preserved, so as to prolong its life cycle. And this object can be read out again if necessary. There are several common modules in Python to implement this function. pickle module Stored in ...

There are many ways to traverse a map in java, from the earliest Iterator to the foreach supported by Java 5 to Java 8 Lambda. Let's look at the specific usage and their respective advantages and disadvantages. Initialize a map first public class TestMap { public static Map<Integer, Integer> map = new HashMap<Integer, Integer>() ...