The urlencode() function is used to encode strings into URL-safe formats, where non-alphanumeric characters (except -, _, and .) are replaced with a percent sign followed by a two-digit hexadecimal number. For example, spaces are converted to signs, exclamation marks are converted to!, and Chinese characters are converted to their UTF-8 encoding form. When using, only the parameter values ??should be encoded, not the entire URL, to avoid damaging the URL structure. For other parts of the URL, such as path segments, the rawurlencode() function should be used, which converts the space to . When processing array parameters, you can use http_build_query() to automatically encode, or manually call urlencode() on each value to ensure safe transfer of data. just

Bitcoin halving affects the price of currency through four aspects: enhancing scarcity, pushing up production costs, stimulating market psychological expectations and changing supply and demand relationships; 1. Enhanced scarcity: halving reduces the supply of new currency and increases the value of scarcity; 2. Increased production costs: miners' income decreases, and higher coin prices need to maintain operation; 3. Market psychological expectations: Bull market expectations are formed before halving, attracting capital inflows; 4. Change in supply and demand relationship: When demand is stable or growing, supply and demand push up prices.

In PHP, you can use square brackets or curly braces to obtain string specific index characters, but square brackets are recommended; the index starts from 0, and the access outside the range returns a null value and cannot be assigned a value; mb_substr is required to handle multi-byte characters. For example: $str="hello";echo$str[0]; output h; and Chinese characters such as mb_substr($str,1,1) need to obtain the correct result; in actual applications, the length of the string should be checked before looping, dynamic strings need to be verified for validity, and multilingual projects recommend using multi-byte security functions uniformly.

There is no legal virtual currency platform in mainland China. 1. According to the notice issued by the People's Bank of China and other departments, all business activities related to virtual currency in the country are illegal; 2. Users should pay attention to the compliance and reliability of the platform, such as holding a mainstream national regulatory license, having a strong security technology and risk control system, an open and transparent operation history, a clear asset reserve certificate and a good market reputation; 3. The relationship between the user and the platform is between the service provider and the user, and based on the user agreement, it clarifies the rights and obligations of both parties, fee standards, risk warnings, account management and dispute resolution methods; 4. The platform mainly plays the role of a transaction matcher, asset custodian and information service provider, and does not assume investment responsibilities; 5. Be sure to read the user agreement carefully before using the platform to enhance yourself

There are two main ways to get the last N characters of a string in PHP: 1. Use the substr() function to intercept through the negative starting position, which is suitable for single-byte characters; 2. Use the mb_substr() function to support multilingual and UTF-8 encoding to avoid truncating non-English characters; 3. Optionally determine whether the string length is sufficient to handle boundary situations; 4. It is not recommended to use strrev() substr() combination method because it is not safe and inefficient for multi-byte characters.

The latest price of Dogecoin can be queried in real time through a variety of mainstream APPs and platforms. It is recommended to use stable and fully functional APPs such as Binance, OKX, Huobi, etc., to support real-time price updates and transaction operations; mainstream platforms such as Binance, OKX, Huobi, Gate.io and Bitget also provide authoritative data portals, covering multiple transaction pairs and having professional analysis tools. It is recommended to obtain information through official and well-known platforms to ensure data accuracy and security.

To set and get session variables in PHP, you must first always call session_start() at the top of the script to start the session. 1. When setting session variables, use $_SESSION hyperglobal array to assign values ??to specific keys, such as $_SESSION['username']='john_doe'; it can store strings, numbers, arrays and even objects, but avoid storing too much data to avoid affecting performance. 2. When obtaining session variables, you need to call session_start() first, and then access the $_SESSION array through the key, such as echo$_SESSION['username']; it is recommended to use isset() to check whether the variable exists to avoid errors

Execution of SELECT queries using PHP's preprocessing statements can effectively prevent SQL injection and improve security. 1. Preprocessing statements separate SQL structure from data, send templates first and then pass parameters to avoid malicious input tampering with SQL logic; 2. PDO and MySQLi extensions commonly used in PHP realize preprocessing, among which PDO supports multiple databases and unified syntax, suitable for newbies or projects that require portability; 3. MySQLi is specially designed for MySQL, with better performance but less flexibility; 4. When using it, you should select appropriate placeholders (such as? or named placeholders) and bind parameters through execute() to avoid manually splicing SQL; 5. Pay attention to processing errors and empty results to ensure the robustness of the code; 6. Close it in time after the query is completed.