Proxy Server Client

Shared proxies should be understood as IPs and port numbers available to everyone. That is, many users can use them simultaneously. The most unreliable and slowest option.

It means routing traffic from multiple devices through a single proxy server. In this way you can, for example, organize a local network in an office environment, but where all the traffic data can be viewed from the administrator's server.

Parsing math expressions correctly involves converting mathematical expressions from their human-readable form into a format that a computer can understand and evaluate. A common approach is to use a parser or library designed for mathematical expressions.

In Python, you can use the sympy library, which provides powerful symbolic mathematics capabilities, including expression parsing and evaluation. Here's an example:

from sympy import sympify, symbols

# Define symbols
x, y = symbols('x y')

# Parse math expressions
expression1 = sympify("2*x + 3*y")
expression2 = sympify("sin(x) + cos(x)")

# Evaluate expressions
result1 = expression1.subs({x: 1, y: 2})
result2 = expression2.subs(x, 0)

print("Result 1:", result1)
print("Result 2:", result2)

In this example, sympify is used to parse the mathematical expressions. You can then substitute values for variables using the subs method.

If you need a more general-purpose parser, you can use the pyparsing library. Here's a basic example:

from pyparsing import Word, nums, operatorPrecedence, opAssoc

# Define grammar for basic math expressions
integer = Word(nums).setParseAction(lambda t: int(t[0]))
variable = Word("xy")
operand = integer | variable
expr = operatorPrecedence(
    operand,
    [
        ("+", 2, opAssoc.LEFT),
        ("-", 2, opAssoc.LEFT),
        ("*", 3, opAssoc.LEFT),
        ("/", 3, opAssoc.LEFT),
    ],
)

# Parse math expressions
expression1 = expr.parseString("2*x + 3*y")
expression2 = expr.parseString("sin(x) + cos(x)")

print("Parsed Expression 1:", expression1)
print("Parsed Expression 2:", expression2)

This example uses pyparsing to define a grammar for basic math expressions with addition, subtraction, multiplication, and division. You can customize the grammar based on your specific needs.

Choose the library that best fits your requirements, whether it's for symbolic mathematics (like sympy) or general-purpose expression parsing (like pyparsing). Always consider error handling and validation when working with user-inputted expressions.

Qt primarily focuses on providing tools and libraries for GUI development, networking, and other application-level features. While it includes facilities for working with XML through classes like QXmlStreamReader and QXmlStreamWriter, these are more geared toward parsing XML rather than HTML.

For HTML parsing, especially when using XPath expressions, you might need to consider additional libraries or tools. One common choice is to use a third-party library like Gumbo or htmlcxx. These libraries are not part of the Qt framework, but they can be used alongside Qt to handle HTML parsing.

Here's a basic example using htmlcxx for HTML parsing:

#include 
#include 
#include 

int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);

    std::string htmlData = "
Hello, world!
";

    htmlcxx::HTML::ParserDom parser;
    tree dom = parser.parseTree(htmlData);

    // Example XPath query
    std::string xpathExpression = "//p/span";
    std::vector::iterator> result;
    htmlcxx::XPath::NodeSet nodeSet;
    htmlcxx::XPath::Parser xpathParser;
    xpathParser.compile(xpathExpression.c_str(), &nodeSet);

    for (tree::iterator it = dom.begin(); it != dom.end(); ++it) {
        nodeSet.evaluate(*it);
        if (nodeSet.size() > 0) {
            result.push_back(it);
        }
    }

    // Output the result
    for (auto &it : result) {
        std::cout << "Match found: " << htmlcxx::HTML::toPlainText(it->begin(), it->end()) << std::endl;
    }

    return a.exec();
}

In this example, I've used htmlcxx for HTML parsing and XPath queries. Note that you need to include the htmlcxx library in your project.

There are 2 ways to do this. The first is to manually change the settings in /etc/environment, but you will definitely need root access to do that. You can also use the Network Manager utility (compatible with all common DEs). You just have to make sure beforehand that the driver for the network adapter to work properly is installed on the system.