The most basic data type of R language-vectors (vector)1, insert the vector element, all elements in the same vector must be the same pattern (data type), such as Integer, numeric (floating-point), character (string), logical, plural, and so on. View the type of the variable can be queried using the typeof (X) function.> #插入向量元素 > x 2, delete the elements in the
Transfer from the blog garden: https://www.cnblogs.com/zhonghuasong/p/5975979.htmlIntroduced
A vector is a sequence container that represents a variable-sized array.
Like arrays, vectors also use contiguous storage spaces to store elements. That means you can use the subscript to access the elements of the vector, as well as the arrays. But unlike an array, its size can be changed dynamically,
Original link: http://blog.csdn.net/cws1214/article/details/47984053
1. Avoid frequent redistribution
One of the most admirable features of STL containers is that they can automatically grow enough to accommodate the data you put in, as long as they are not larger than their maximum size. (To know the maximum value, just call the member function named Max_size.) )
For vectors and strings, if more space is needed, the size is increased by a similar realloc thought. This realloc-like operation ha
In practice, the vector series in c ++-C ++ 11 extends the vector member functions (cbegin (), cend (), crbegin (), crend (), and emplace (), data ())
The emplace_back mentioned above is added to C ++ 11.
Therefore, this blog just wants to list how C ++ 11 expands the vector container.
Std: vector: cbegin and std:
Before doing a bit of something, to fit 6 and plus, do your own cut map to find it really annoying enough. The method of generating PNG graphics based on vector graph is also afterwards know, study, hope next can practice. Enter the translation below.
The visual form of iOS applications is usually driven by graphical elements. When designing and developing an application, you need different specifications for application icons, such as default.png pi
In practice, the vector series in c ++ -- copy set to vector (do not confuse reserve and resize)
The stl algorithm has a copy function. We can easily write this Code:
#include
#include #include
using namespace std;int _tmain(int argc, _TCHAR* argv[]){ double darray[10]={1.0,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9}; vector
vdouble(10);
Previously only used vectorFirst, JTable and DefaultTableModel.JTable itself is a list that can be displayed, but cannot be monitored by the button to increase the positive row data.JTable no AddRow (object[] rowdata) or addrow (Vector rowdata), method.But there is a construction method in JTable, JTable (TableModel DM)And TableModel is an interface that implements this interface with a common class DefaultTableModel. There is a method in DefaultTable
Data Growth:When you need to increase, VectorThe default growth is the original one training, andArraylistHalf of the originalSynchronization: the vector is thread-safe, that is, synchronous, And the arraylist is a line.ProgramNot secure, not synchronous
Here we can look at their source code to know:
The size () method of arraylist:
1 /**2 * Returns the number of elements in this list.3 *4 *@ ReturnThe number of elements in this list5*/6Public In
JDK source code-Vector, jdk-vector1, Vector:-1, an array of objects that can grow. Similar to an object array, it contains an integer index for component access. However, the Vector size can be increased or reduced as needed.-2. Each Vector optimizes storage management by maintaining capacity and capacityIncrement. Cap
Vector applications (element traversal, insertion, deletion, switching, etc.), vectorHere is a summary of some common applications of vector containers. For the vector constructor and initialization, refer to http://blog.csdn.net/lsh_2013/article/details/21191289. Element Traversal
Use an iterator to access a vector El
Label: gradient descent method, cut vector, method Vector Zookeeper First, it indicates that the gradient is perpendicular to the cut vector of the curve, that is, the gradient direction is the direction of the normal vector: Set the curve x = x (t), Y = Y (T), and z = z (T) to the surface u (x, y, z) = a curve on C (
C ++ is based on the vector graphics library cairo graphics, vector graphics cairo
// Sudo apt-get install libcairo2-dev // pkg-config -- cflags -- libs cairo //-I/usr/include/cairo-I/usr/include/glib-2.0-I /usr/lib/x86_64-linux-gnu/glib-2.0/include-I/usr/include/pixman-1-I/usr/include/freetype2-I/usr/include/libpng12-lcairo # include
Compilation in Ubuntu:
G ++ 'pkg-config -- cflags cairo 'test_cairo.cpp
Today, I have nothing to do with it. I 've been reading about it for a long time on my computer.
When I saw 43rd entries, I found that, as mentioned above, the algorithm replaces the manual loop.
No doubt arises.
I remember the operator [] operation (subscript operation) was the most efficient loop when I read the vector source code ).
The algorithm is fast.
The following is a test code:
// Test class and call Function
Class AAA{Public:Void MakeFul
C ++ Study Notes (15th): How the vector object grows in the memory space, learning notes vector
How does a vector object increase in memory?
We all know that vector objects are dynamically stored. From this point of view, they are a bit like linked lists, which can dynamically increase or decrease elements. We also kn
Vector series in practice c ++ -- use std: find and std: find_if algorithms for vector (custom class)
Previously, my blog talked about some usage of std: find and std: find _ if, but not about the custom class stored in the vector. How to Use std:: find and std: find_if?
First define a class:
class Item{private: std::string m_ItemId; int m_Price; int m_
Vector or arraylist-which one is better? Why?
The answer to this question cannot be generalized. Sometimes it is better to use vector. Sometimes it is an arraylist. Sometimes neither of them is
The best choice. Don't expect a simple affirmative answer, because it depends on what you use them. Four of the following are to be considered:
Factors:
L API
L synchronous processing
L data growth
L usage mode
We wi
In practice, the vector series in c ++ -- Some vector exceptions
Today, we will write some vector exceptions that can be captured.
Out_of_rangeThe array is out of bounds. The vector automatically increases the capacity, but if the index exceeds the current size, an exception is thrown.
# Include
# Include
Label: style blog HTTP color OS Io ar Div html When setting the CPU parameters during the learning process of the nioshi II, the Reset vector and exception vector settings are encountered. Shows the parameter setting screen. Reset vector -- Reset vectorException vector -- execution VectorFirst, it indicates that both
As in the title, if I were to answer before, I would say, yes, in the multi-threaded environment to operate the vector, do not need to add synchronized.But I accidentally saw an article today, I found that my previous idea was wrong, the address of this article:http://zhangbq168.blog.163.com/blog/static/2373530520082332459511/I extract the key part:Vectors are slower than ArrayList because the vectors themselves are synchronized, and ArrayList is notT
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