vectors png

PS: This blog is mainly about the underlying source code of the JDK. Rather than write your own code.Excuse me ArrayList , LinkedList , Vector the Difference① ArrayList The underlying is actually implemented with an array (and the type of the array Object type of)② hypothesis Jdk6 , using array.copyof () method to generate a new array, assuming that the Jdk5 , the use is system.arraycopy () method (when the amount of data added is greater than the length of the array)③ List List = Newarraylist (

Today, we studied the source code of vector and ArrayList, and deepened the understanding of these two classes.A total of three classes are implemented under the list interface: Arraylist,vector,linkedlist. LinkedList not much to say, it is generally used to keep the data in the order of insertion. ArrayList and vectors are all implemented using arrays, and there are three differences:1, vector is multithreaded security, and ArrayList is not, this can

Erase usage considerations in vectors-daofengdeba-Blog channel-csdn.nethttp://blog.csdn.net/daofengdeba/article/details/7865229For (Vector{if (*iter = = 3)iter = Veci.erase (ITER);ElseITER + +;This is the case after the test canVectorFor (Vector{if (*iter = = 3){Itor2=iter;Veci.erase (ITOR2);}ElseITER + +;This method after the test or errorErase used in vectors

1. Vector ArrayList1) Vector methods are synchronous (Synchronized), is thread-safe (Thread-safe), and ArrayList method is not, because the synchronization of threads will inevitably affect performance, therefore, ArrayList performance is better than vector.2) When an element in a vector or ArrayList exceeds its initial size, the vector doubles its capacity and ArrayList only increases its size by 50%, so that the ArrayList is useful for saving memory space.2. Hashtable HashMapThe performance

Welcome to follow my GitHub and follow my csdn. ERA in the development of technology in progress, the era of Android vector images has arrived. In Google's latest support library v23.2, the AppCompat class already uses vector imagery, which reduces the AAR package by 9% to about 70KB, benefiting all high-version applications. Of course we can also use vector, slimming applications. Vector images are the SVG format in the form of Android. SVG image to adapt to the screen, the picture is smal

use ArrayList, because it is more efficient than thread-safe, and if there are multiple lines routines access to the collection, it is best to use vectors, since we do not need to consider and write thread-safe code ourselves.Note: For Vectorarraylist, Hashtablehashmap, to remember the problem of thread safety, remember that the vector and Hashtable are old, Java is a birth to provide, they are thread-safe, ArrayList and HashMap are provided at JAVA2

In essential C + + a book after the answer to question 1-6, there is a new discovery.The topics are summarized as follows:Write a program that reads an integer from the standard input device and places the integer that is being read into the array and vector, and then iterates through the two containers to find the sum of the values. Outputs the sum and the average to the standard output device.Answer code:Solving problems with vectors#include #includ

§ 7 Number product of two vectors Definition 1For two vectorsAAndB, Modulo them |A|, |B| And their angleQThe product of the cosine is called the number product of the vector and recordedAB,That is AB= |A|B| CosQ. The relationship between the definition and projection is available. AB= |B| PrjbA = |A| PrjaB. The nature of the number product: (1)A.= |A| 2, noteA.=A2, thenA2 = |A| 2. (2) For two non-zero vectorsA,B, IfA · B= 0, thenA^B Otherwise, ifA^B,

........ Some exceptions, such as in FORTRANColumn priorityThe storage sequence is N10, N20, n30...... N11, n21...... n12, n22, and so on. No matter how many dimensions, this is the case. The advantage of the array is that the access speed is fast. The disadvantage is that the size of the array has been determined during the Declaration and cannot be expanded. Vector(Vector container)Vector is often used. In fact, a vector is a dynamic array. The so-called dynamic means that the array can grow

How to calculate the outer product of two arrays (or vectors) in the R language? The outer product of arrays (or vectors) a and B refers to the new elements obtained by multiplying each element of a and each element of B together. of course, operation rules can also be customized. the outer product operator is % o % (note: the letter in the middle of the percent is the lowercase letter o ). for example:

:42) at Java.util.concurrent.executors$runnableadapter.call (Executors.java:471) at Java.util.concurrent.FutureTask.run (Futuretask.java:262) at Java.util.concurrent.ThreadPoolExecutor.runWorker (Threadpoolexecutor.java:1145) at Java.util.concurrent.threadpoolexecutor$worker.run (Threadpoolexecutor.java:615) at Java.lang.Thread.run (Thread.java:744)Obviously, vector is thread-safe, why is there such a problem here? CTRL + Left click, view source code, found that almost all methods of vector clas

. The defect value is also counted in length.4.1.3 namingOne big feature of r vectors is the ability to name each element. In general, markup elements can make code more readable.x 4.1.4 Index VectorIn general, we only have to access parts or individual elements in the vector. This is the so-called index, which he implements with square brackets [].1. If you pass a positive number to a vector, it returns a vector element slice at this position. His fi